World War II

===Course of the war===
{{For timeline|List of timelines of World War II}}
{{See also|Diplomatic history of World War II|World War II by country}} 

====War breaks out in Europe (1939–1940)====
{{Main|European theatre of World War II}}
[[File:Germans at Polish Border (1939-09-01).jpg|thumb|Soldiers of the German ''[[Wehrmacht]]'' tearing down the border crossing into [[Second Polish Republic|Poland]], 1 September 1939]]

On 1 September 1939, Germany [[Invasion of Poland|invaded Poland]] after [[Operation Himmler|having staged]] several [[Gleiwitz incident|false flag border incidents]] as a pretext to initiate the invasion.{{sfn|Evans|2008|pp=1–2}} The first German attack of the war came against the [[Battle of Westerplatte|Polish defenses at Westerplatte]].<ref name="Zabecki2015">{{cite book|url=https://books.google.com/books?id=Mq_lCAAAQBAJ&pg=PT1663|title=World War II in Europe: An Encyclopedia|author=David T. Zabecki|date=2015|publisher=Routledge|isbn=978-1-135-81242-3|page=1663|quote=The earliest fighting started at 0445 hours when marines from the battleship Schleswig-Holstein attempted to storm a small Polish fort in Danzig, the Westerplate|access-date=17 June 2019|archive-date=7 March 2023|archive-url=https://web.archive.org/web/20230307201256/https://books.google.com/books?id=Mq_lCAAAQBAJ&pg=PT1663|url-status=live}}</ref> The United Kingdom responded with an ultimatum for Germany to cease military operations, and on 3 September, after the ultimatum was ignored, Britain and France declared war on Germany,<ref>[[United Kingdom declaration of war on Germany (1939)|The UK declared war on Germany]] at 11 am. [[French declaration of war on Germany (1939)|France followed 6 hours later]] at 5 pm.</ref> followed by [[Australia]], [[Dominion of New Zealand|New Zealand]], [[Union of South Africa|South Africa]], and [[Canada]]. During the [[Phoney War]] period, the alliance provided no direct military support to Poland, outside of a [[Saar Offensive|cautious French probe into the Saarland]].<ref name="Keegan 1997 35">{{Harvnb|Keegan|1997|p=35}}.<br />{{Harvnb|Cienciala|2010|p=128}}, observes that, while it is true that Poland was far away, making it difficult for the French and British to provide support, "[f]ew Western historians of World War&nbsp;II&nbsp;... know that the British had committed to bomb Germany if it attacked Poland, but did not do so except for one raid on the base of Wilhelmshaven. The French, who committed to attacking Germany in the west, had no intention of doing so."</ref> The Western Allies also began a [[Blockade of Germany (1939–1945)|naval blockade of Germany]], which aimed to damage the country's economy and war effort.<ref>{{Harvnb|Beevor|2012|p=32}}; {{Harvnb|Dear|Foot|2001|pp=248–249}}; {{Harvnb|Roskill|1954|p=64}}.</ref> Germany responded by ordering [[Submarine warfare#World War II|U-boat warfare]] against Allied merchant and warships, which would later escalate into the [[Battle of the Atlantic]].<ref>{{Cite web |title=Battle of the Atlantic |url=https://www.history.co.uk/history-of-ww2/battle-of-the-atlantic |access-date=11 July 2022 |website=Sky HISTORY TV channel |language=en |archive-date=20 May 2022 |archive-url=https://web.archive.org/web/20220520073745/https://www.history.co.uk/history-of-ww2/battle-of-the-atlantic |url-status=live }}</ref>

On 8 September, German troops reached the suburbs of [[Warsaw]]. The Polish [[Battle of the Bzura|counter-offensive]] to the west halted the German advance for several days, but it was outflanked and encircled by the ''[[Wehrmacht]]''. Remnants of the Polish army broke through to [[Siege of Warsaw (1939)|besieged Warsaw]]. On 17 September 1939, two days after signing a [[Battles of Khalkhin Gol|cease-fire with Japan]], the [[Soviet invasion of Poland|Soviet Union invaded Poland]]{{sfn|Zaloga|2002|pp=80, 83}} under the supposed pretext that the Polish state had ceased to exist.<ref>{{Cite journal |jstor = 2195670|title = A Case Study in the Soviet Use of International Law: Eastern Poland in 1939|journal = The American Journal of International Law|volume = 52|issue = 1|pages = 69–84|last1 = Ginsburgs|first1 = George|year = 1958|doi = 10.2307/2195670|s2cid = 146904066}}</ref> On 27 September, the Warsaw garrison surrendered to the Germans, and [[Independent Operational Group Polesie|the last large operational unit of the Polish Army]] [[Battle of Kock (1939)|surrendered on 6{{nbsp}}October]]. Despite the military defeat, Poland never surrendered; instead, it formed the [[Polish government-in-exile]] and a [[Polish Underground State|clandestine state apparatus remained]] in occupied Poland.{{sfn|Hempel|2005|p=24}} A significant part of Polish military personnel [[Romanian Bridgehead|evacuated to Romania]] and Latvia; many of them later [[Military history of Poland during World War II|fought against the Axis]] in other theatres of the war.{{sfn|Zaloga|2002|pp=88–89}}

Germany [[Polish areas annexed by Nazi Germany|annexed western]] Poland and [[General Government|occupied central Poland]]; the Soviet Union [[Territories of Poland annexed by the Soviet Union|annexed eastern Poland]]; small shares of Polish territory were transferred to [[Territorial evolution of Poland#World War II|Lithuania]] and [[Slovak invasion of Poland|Slovakia]]. On 6 October, Hitler made a public peace overture to the United Kingdom and France but said that the future of Poland was to be determined exclusively by Germany and the Soviet Union. The proposal was rejected<ref name=ibiblio1939 /> and Hitler ordered an immediate offensive against France,<ref>Nuremberg Documents C-62/GB86, a directive from Hitler in October 1939 which concludes: "The attack [on France] is to be launched this Autumn if conditions are at all possible."</ref> which was postponed until the spring of 1940 due to bad weather.{{sfn|Liddell Hart|1977|pp=39–40}}{{sfn|Bullock|1990|loc=pp. 563–64, 566, 568–69, 574–75 (1983 ed.)}}<ref>Blitzkrieg: From the Rise of Hitler to the Fall of Dunkirk, L Deighton, Jonathan Cape, 1993, pp. 186–87. Deighton states that "the offensive was postponed twenty-nine times before it finally took place."</ref>

[[File:Karelian Isthmus 13 March 1940.png|thumb|left|[[Mannerheim Line]] and [[Karelian Isthmus]] on the last day of the [[Winter War]], 13 March 1940]]
After the outbreak of war in Poland, Stalin threatened [[Estonia]], [[Latvia]], and [[Lithuania]] with military invasion, forcing the three [[Baltic states|Baltic countries]] to sign [[Background of the occupation of the Baltic states#Soviet ultimatums and occupation|pacts]] allowing the creation of Soviet military bases in these countries; in October 1939, significant Soviet military contingents were moved there.{{sfn|Smith|Pabriks|Purs|Lane|2002|p=24}}{{sfn|Bilinsky|1999|p=9}}{{sfn|Murray|Millett|2001|pp=55–56}} [[Finland]] refused to sign a similar pact and rejected ceding part of its territory to the Soviet Union. [[Winter War#Soviet invasion|The Soviet Union invaded Finland]] in November 1939,{{sfn|Spring|1986|pp=207–226}} and was subsequently expelled from the [[League of Nations]] for this crime of aggression.<ref>Carl van Dyke. ''The Soviet Invasion of Finland''. Frank Cass Publishers, Portland, OR. {{ISBN|978-0-7146-4753-1}}, p. 71.</ref> Despite overwhelming numerical superiority, Soviet military success during the [[Winter War]] was modest,<ref>{{cite web|url=https://www.warhistoryonline.com/war-articles/winter-war-finland.html|title=The Winter War – When the Finns Humiliated the Russians|first=Ivano|last=Massari|publisher=War History Online|date=18 August 2015|access-date=19 December 2021|archive-date=19 December 2021|archive-url=https://web.archive.org/web/20211219185618/https://www.warhistoryonline.com/war-articles/winter-war-finland.html|url-status=live}}</ref> and the Finno-Soviet war ended in March 1940 with [[Moscow Peace Treaty|some Finnish concessions of territory]].{{sfn|Hanhimäki|1997|p=12}}

In June 1940, the Soviet Union [[Soviet occupation of the Baltic states (1940)|occupied]] the entire territories of Estonia, Latvia and Lithuania,{{sfn|Bilinsky|1999|p=9}} as well as the Romanian regions of [[Soviet occupation of Bessarabia and Northern Bukovina|Bessarabia, Northern Bukovina, and the Hertsa region]]. In August 1940, Hitler imposed the [[Second Vienna Award]] on Romania which led to the transfer of [[Northern Transylvania]] to Hungary.{{sfn|Dear|Foot|2001|pp=745, 975}} In September 1940, Bulgaria demanded [[Southern Dobruja]] from Romania with German and Italian support, leading to the [[Treaty of Craiova]].<ref name="Haynes-2000">{{cite book|url=https://books.google.com/books?id=b_I-AQAAIAAJ|title=Romanian policy towards Germany, 1936–40|first=Rebecca|last=Haynes|publisher=[[Palgrave Macmillan]]|page=205|year=2000|isbn=978-0-312-23260-3|access-date=3 February 2022|archive-date=7 March 2023|archive-url=https://web.archive.org/web/20230307201243/https://books.google.com/books?id=b_I-AQAAIAAJ|url-status=live}}</ref> The loss of one-third of Romania's 1939 territory caused a coup against King Carol II, turning Romania into a fascist dictatorship under Marshal [[Ion Antonescu]], with a course set towards the Axis in the hopes of a German guarantee.<ref>Deletant, pp. 48–51, 66; Griffin (1993), p. 126; Ornea, pp. 325–327</ref> Meanwhile, German-Soviet political relations and economic co-operation{{sfn|Ferguson|2006|pp=367, 376, 379, 417}}{{sfn|Snyder|2010|pp=118ff}} gradually stalled,{{sfn|Koch|1983|pp=912–914, 917–920}}{{sfn|Roberts|2006|p=56}} and both states began preparations for war.{{sfn|Roberts|2006|p=59}}

====Western Europe (1940–1941)====
{{Main|Western Front (World War II)}}
[[File:WWIIEuropeMay40.gif|thumb|upright=1.4|German advance into Belgium and Northern France, 10 May{{snd}}4 June 1940, swept past the [[Maginot Line]] (shown in dark red)]]

In April 1940, [[Operation Weserübung|Germany invaded Denmark and Norway]] to protect shipments of [[Swedish iron-ore industry during World War II|iron ore from Sweden]], which the Allies were [[Operation Wilfred|attempting to cut off]].<ref>{{Harvnb|Murray|Millett|2001|pp=57–63}}.</ref> [[German invasion of Denmark (1940)|Denmark capitulated after six hours]], and [[Norwegian campaign|despite Allied support]], Norway was conquered within two months.{{sfn|Commager|2004|p=9}} [[Norway Debate|British discontent over the Norwegian campaign]] led to the resignation of Prime Minister [[Neville Chamberlain]], who was replaced by [[Winston Churchill]] on 10{{spaces}}May 1940.{{sfn|Reynolds|2006|p=76}}

On the same day, Germany [[Battle of France|launched an offensive against France]]. To circumvent the strong [[Maginot Line]] fortifications on the Franco-German border, Germany directed its attack at the neutral nations of [[German invasion of Belgium (1940)|Belgium]], [[German invasion of the Netherlands|the Netherlands]], and [[German invasion of Luxembourg|Luxembourg]].{{sfn|Evans|2008|pp=122–123}} The Germans carried out a flanking manoeuvre through the [[Ardennes]] region,{{sfn|Keegan|1997|pp=59–60}} which was mistakenly perceived by the Allies as an impenetrable natural barrier against armoured vehicles.{{sfn|Regan|2004|p=152}}{{sfn|Liddell Hart|1977|p=48}} By successfully implementing new ''[[Blitzkrieg]]'' tactics, the ''Wehrmacht'' rapidly advanced to the Channel and cut off the Allied forces in Belgium, trapping the bulk of the Allied armies in a cauldron on the Franco-Belgian border near Lille. The United Kingdom was able [[Dunkirk evacuation|to evacuate a significant number of Allied troops]] from the continent by early June, although they had to abandon almost all their equipment.{{sfn|Keegan|1997|pp=66–67}}

On 10 June, [[Italian invasion of France|Italy invaded France]], declaring war on both France and the United Kingdom.{{sfn|Overy|Wheatcroft|1999|p=207}} The Germans turned south against the weakened French army, and [[Paris in World War II|Paris]] fell to them on 14{{spaces}}June. Eight days later [[Armistice of 22 June 1940|France signed an armistice with Germany]]; it was divided into [[German military administration in occupied France during World War II|German]] and [[Italian occupation of France|Italian occupation zones]],{{sfn|Umbreit|1991|p=311}} and an unoccupied [[rump state]] under the [[Vichy France|Vichy Regime]], which, though officially neutral, was generally aligned with Germany. France kept its fleet, which [[Attack on Mers-el-Kébir|the United Kingdom attacked]] on 3{{spaces}}July in an attempt to prevent its seizure by Germany.{{sfn|Brown|2004|p=198}}

[[File:View from St Paul's Cathedral after the Blitz.jpg|left|thumb|[[London]] seen from [[St Paul's Cathedral]] after the German [[The Blitz|''Blitz'']], 29 December 1940]]
The air [[Battle of Britain]]{{sfn|Keegan|1997|p=[{{GBurl|id=TF8kcx9hTssC|p=72}} 72]}} began in early July with [[Kanalkampf|Luftwaffe attacks on shipping and harbours]].<ref name=Murray_BoB>{{harvnb|Murray|1983|loc=[https://www.ibiblio.org/hyperwar/AAF/AAF-Luftwaffe/AAF-Luftwaffe-2.html#cn70 The Battle of Britain].}}</ref> The United Kingdom rejected Hitler's peace offer,<ref name=ibiblio_1940>{{cite web |title=Major international events of 1940, with explanation |url=https://www.ibiblio.org/pha/events/1940.html |publisher=Ibiblio.org |archive-url=https://web.archive.org/web/20130525060313/https://www.ibiblio.org/pha/events/1940.html |archive-date=25 May 2013 |url-status=live}}</ref> and the [[Adlertag|German air superiority campaign]] started in August but failed to defeat [[RAF Fighter Command]], forcing the indefinite postponement of the [[Operation Sea Lion|proposed German invasion of Britain]]. The German [[strategic bombing]] offensive intensified with night attacks on London and other cities in [[the Blitz]], but largely ended in May 1941{{sfn|Dear|Foot|2001|pp=108–109}} after failing to significantly disrupt the British war effort.{{r|Murray_BoB}}

Using newly captured French ports, the German Navy [[Battle of the Atlantic#'The Happy Time' (June 1940 – February 1941)|enjoyed success]] against an over-extended [[Royal Navy]], using [[U-boat]]s against British shipping [[Battle of the Atlantic|in the Atlantic]].<ref>{{Harvnb|Goldstein|2004|p=35}}</ref> The British [[Home Fleet]] scored a significant victory on 27{{spaces}}May 1941 by [[Last battle of Bismarck|sinking the German battleship ''Bismarck'']].<ref>{{Harvnb|Steury|1987|p=209}}; {{Harvnb|Zetterling|Tamelander|2009|p=282}}.</ref>

In November 1939, the United States was assisting China and the Western Allies, and had amended the [[Neutrality Acts of the 1930s|Neutrality Act]] to allow [[Cash and carry (World War II)|"cash and carry"]] purchases by the Allies.{{sfn|Overy|Wheatcroft|1999|pp=328–330}} In 1940, following the German capture of Paris, the size of the [[United States Navy]] was [[Two-Ocean Navy Act|significantly increased]]. In September the United States further agreed to a [[Destroyers-for-bases deal|trade of American destroyers for British bases]].{{sfn|Maingot|1994|p=52}} Still, a large majority of the American public continued to oppose any direct military intervention in the conflict well into 1941.{{sfn|Cantril|1940|p=390}} In December 1940, Roosevelt accused Hitler of planning world conquest and ruled out any negotiations as useless, calling for the United States to become an "[[Arsenal of Democracy|arsenal of democracy]]" and promoting [[Lend-Lease]] programmes of military and humanitarian aid to support the British war effort; Lend-Lease was later extended to the other Allies, including the Soviet Union after it was [[Operation Barbarossa|invaded]] by Germany.{{r|ibiblio_1940}} The United States started strategic planning to prepare for a full-scale offensive against Germany.<ref>{{cite web |author=Skinner Watson, Mark |title=Coordination With Britain |website=US Army in WWII – Chief of Staff: Prewar Plans and Operations |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Plans/USA-WD-Plans-12.html |access-date=13 May 2013 |archive-url=https://web.archive.org/web/20130430001549/https://www.ibiblio.org/hyperwar/USA/USA-WD-Plans/USA-WD-Plans-12.html |archive-date=30 April 2013 |url-status=live}}</ref>

At the end of September 1940, the [[Tripartite Pact]] formally united Japan, Italy, and Germany as the [[Axis powers]]. The Tripartite Pact stipulated that any country—with the exception of the Soviet Union—that attacked any Axis Power would be forced to go to war against all three.{{Sfn|Bilhartz|Elliott|2007|p=179}} The Axis expanded in November 1940 when [[Kingdom of Hungary (1920–1946)|Hungary]], [[Slovak Republic (1939–1945)|Slovakia]], and [[Kingdom of Romania|Romania]] joined.{{Sfn|Dear|Foot|2001|p=877}} [[Romania in World War II|Romania]] and [[Hungary in World War II|Hungary]] later made major contributions to the Axis war against the Soviet Union, in Romania's case partially to recapture [[Soviet occupation of Bessarabia and Northern Bukovina|territory ceded to the Soviet Union]].{{Sfn|Dear|Foot|2001|pp=745–746}}

====Mediterranean (1940–1941)====
{{Main|Mediterranean and Middle East theatre of World War II}}

In early June 1940, the Italian ''Regia Aeronautica'' [[Siege of Malta (World War II)|attacked and besieged Malta]], a British possession. From late summer to early autumn, Italy [[Italian invasion of British Somaliland|conquered British Somaliland]] and made an [[Italian invasion of Egypt|incursion into British-held Egypt]]. In October, [[Greco-Italian War|Italy attacked Greece]], but the attack was repulsed with heavy Italian casualties; the campaign ended within months with minor territorial changes.{{sfn|Clogg|2002|p=118}} To assist Italy and prevent Britain from gaining a foothold, Germany prepared to invade the Balkans, which would threaten Romanian oil fields and strike against British dominance of the Mediterranean.<ref>{{Harvnb|Evans|2008|pp=146, 152}}; {{Harvnb|US Army|1986|pp=[https://www.history.army.mil/books/wwii/balkan/20_260_1.htm 4–6]}}</ref>

[[File:Bundesarchiv Bild 101I-783-0109-11, Nordafrika, Panzer III in Fahrt.jpg|thumb|German [[Panzer III]] of the [[Afrika Korps]] advancing across the North African desert, April–May 1941]]
In December 1940, British Empire forces began [[Operation Compass|counter-offensives]] against Italian forces in Egypt and [[East African campaign (World War II)|Italian East Africa]].{{sfn|Jowett|2001|pp=9–10}} The offensives were successful; by early February 1941, Italy had lost control of eastern Libya, and large numbers of Italian troops had been taken prisoner. The [[Regia Marina|Italian Navy]] also suffered significant defeats, with the Royal Navy putting three Italian battleships out of commission after a [[Battle of Taranto|carrier attack at Taranto]], and neutralising several more warships at the [[Battle of Cape Matapan]].{{sfn|Jackson|2006|p=106}}

Italian defeats prompted Germany to [[Operation Sonnenblume|deploy an expeditionary force]] to North Africa; at the end of March 1941, [[Erwin Rommel|Rommel]]'s [[Afrika Korps]] [[Western Desert campaign|launched an offensive]] which drove back Commonwealth forces.{{sfn|Laurier|2001|pp=7–8}} In less than a month, Axis forces advanced to western Egypt and [[Siege of Tobruk|besieged the port of Tobruk]].{{sfn|Murray|Millett|2001|pp=263–276}}

By late March 1941, [[Bulgaria]] and [[Yugoslavia]] signed the [[Tripartite Pact]]; however, the Yugoslav government was [[Yugoslav coup d'état|overthrown two days later]] by pro-British nationalists. Germany and Italy responded with simultaneous invasions of both [[Invasion of Yugoslavia|Yugoslavia]] and [[German invasion of Greece|Greece]], commencing on 6 April 1941; both nations were forced to surrender within the month.{{sfn|Gilbert|1989|pages=174–175}} The airborne [[Battle of Crete|invasion of the Greek island of Crete]] at the end of May completed the German conquest of the Balkans.{{sfn|Gilbert|1989|pages=184–187}} Partisan warfare subsequently broke out against the [[World War II in Yugoslavia|Axis occupation of Yugoslavia]], which continued until the end of the war.{{sfn|Gilbert|1989|pages=208, 575, 604}}

In the Middle East in May, Commonwealth forces [[Anglo-Iraqi War|quashed an uprising in Iraq]] which had been supported by German aircraft from bases within Vichy-controlled [[Mandate for Syria and the Lebanon|Syria]].{{sfn|Watson|2003|p=80}} Between June and July, British-led forces [[Syria–Lebanon campaign|invaded and occupied the French possessions of Syria and Lebanon]], assisted by the [[Free France|Free French]].<ref>{{Citation|last=Morrisey|first=Will|chapter=What Churchill and De Gaulle learned from the Great War|date=2019|pages=119–126|publisher=Routledge|isbn=978-0-429-02764-2|doi=10.4324/9780429027642-6|title=Winston Churchill|s2cid=189257503}}</ref>

====Axis attack on the Soviet Union (1941)====
{{Main|Eastern Front (World War II)}}
[[File:Second world war europe animation large de.gif|thumb|upright=1.2|[[European theatre of World War&nbsp;II]] animation map, 1939–1945 – Red: [[Allies of World War II|Western Allies]] and the Soviet Union after 1941; Green: [[Soviet Union]] before 1941; Blue: [[Axis powers]]]]

With the situation in Europe and Asia relatively stable, Germany, Japan, and the Soviet Union made preparations for war. With the Soviets wary of mounting tensions with Germany, and the Japanese planning to take advantage of the European War by seizing resource-rich European possessions in [[Southeast Asia]], the two powers signed the [[Soviet–Japanese Neutrality Pact]] in April 1941.{{sfn|Garver|1988|p=114}} By contrast, the Germans were steadily making preparations for an attack on the Soviet Union, massing forces on the Soviet border.{{sfn|Weinberg|2005|p=195}}

Hitler believed that the United Kingdom's refusal to end the war was based on the hope that the United States and the Soviet Union would enter the war against Germany sooner or later.{{sfn|Murray|1983|p=[https://www.ibiblio.org/hyperwar/AAF/AAF-Luftwaffe/AAF-Luftwaffe-3.html 69]}} On 31 July 1940, Hitler decided that the Soviet Union should be eliminated and aimed for the conquest of [[Ukrainian Soviet Socialist Republic|Ukraine]], the [[Baltic states]] and [[Byelorussian Soviet Socialist Republic|Byelorussia]].<ref name="GSWW4_26">{{Harvnb|Förster|1998|p=26}}.</ref> However, other senior German officials like Ribbentrop saw an opportunity to create a Euro-Asian bloc against the British Empire by inviting the Soviet Union into the Tripartite Pact.<ref name="GSWW4_38">{{Harvnb|Förster|1998|pp=38–42}}.</ref> In November 1940, [[German–Soviet Axis talks|negotiations took place]] to determine if the Soviet Union would join the pact. The Soviets showed some interest but asked for concessions from Finland, Bulgaria, Turkey, and Japan that Germany considered unacceptable. On 18 December 1940, Hitler issued the directive to prepare for an invasion of the Soviet Union.{{sfn|Shirer|1990|pp=810–812}}

On 22 June 1941, Germany, supported by Italy and Romania, invaded the Soviet Union in [[Operation Barbarossa]], with Germany accusing the Soviets of [[Soviet offensive plans controversy|plotting against them]]; they were joined shortly by Finland and Hungary.<ref name=Events1941>{{citation |last1=Klooz |first1=Marle |last2=Wiley |first2=Evelyn |others=Director: Humphrey, Richard A. |year=1944 |title=Events leading up to World War II – Chronological History |series=78th Congress, 2d Session – House Document N. 541 |location=Washington, DC |publisher=US Government Printing Office |at=pp. 267–312 ([https://www.ibiblio.org/pha/events/1941.html 1941]) |url=https://www.ibiblio.org/pha/events/ |access-date=9 May 2013 |archive-url=https://web.archive.org/web/20131214113907/https://www.ibiblio.org/pha/events/ |archive-date=14 December 2013 |url-status=live}}</ref> The primary targets of this surprise offensive{{sfn|Sella|1978|p=555}} were the [[Baltic region]], Moscow and Ukraine, with the [[Strategic goal (military)|ultimate goal]] of ending the 1941 campaign near the [[A-A line|Arkhangelsk-Astrakhan line]]—from the [[Caspian Sea|Caspian]] to the [[White Sea]]s. Hitler's objectives were to eliminate the Soviet Union as a military power, exterminate [[Communism]], generate ''[[Lebensraum]]'' ("living space"){{sfn|Kershaw|2007|pp=66–69}} by [[Generalplan Ost|dispossessing the native population]],{{sfn|Steinberg|1995}}<!--please, don't add "page needed" template: it is a journal article--> and guarantee access to the strategic resources needed to defeat Germany's remaining rivals.{{sfn|Hauner|1978}}<!--please, don't add "page needed" template: it is a journal article-->

Although the [[Red Army]] was preparing for strategic [[counter-offensive]]s before the war,{{sfn|Roberts|1995}}<!--please, don't add "page needed" template: it is a journal article--> ''Operation'' ''Barbarossa'' forced the [[Stavka|Soviet supreme command]] to adopt [[strategic defence]]. During the summer, the Axis made significant gains into Soviet territory, inflicting immense losses in both personnel and materiel<!-- not a typo -->. By mid-August, however, the German [[Oberkommando des Heeres|Army High Command]] decided to [[Battle of Smolensk (1941)|suspend the offensive]] of a considerably depleted [[Army Group Centre]], and to divert the [[2nd Panzer Army|2nd Panzer Group]] to reinforce troops advancing towards central Ukraine and Leningrad.{{sfn|Wilt|1981}}<!--please, don't add "page needed" template: it is a journal article--> The [[Battle of Kiev (1941)|Kiev offensive]] was overwhelmingly successful, resulting in encirclement and elimination of four Soviet armies, and made possible further [[Crimean campaign|advance into Crimea]] and industrially-developed Eastern Ukraine (the [[First Battle of Kharkov]]).{{sfn|Erickson|2003|pp=114–137}}

[[File:RIAN archive 2153 After bombing.jpg|thumb|Russian civilians leaving destroyed houses after a German bombardment during the [[siege of Leningrad]] ([[Saint Petersburg]]), 10 December 1942]]
The diversion of three-quarters of the Axis troops and the majority of their air forces from France and the central Mediterranean to the [[Eastern Front (World War II)|Eastern Front]]{{sfn|Glantz|2001|p=9}} prompted the United Kingdom to reconsider its [[grand strategy]].{{sfn|Farrell|1993}}<!--please, don't add "page needed" template: it is a journal article--> In July, the UK and the Soviet Union formed a [[Anglo-Soviet Agreement|military alliance against Germany]]{{sfn|Keeble|1990|p=29}} and in August, the United Kingdom and the United States jointly issued the [[Atlantic Charter]], which outlined British and American goals for the post-war world.{{sfn|Beevor|2012|p=220}} In late August the British and Soviets [[Anglo-Soviet invasion of Iran|invaded neutral Iran]] to secure the [[Persian Corridor]], Iran's [[oil fields]], and preempt any Axis advances through Iran toward the Baku oil fields or India.{{sfn|Bueno de Mesquita|Smith|Siverson|Morrow|2003|p=425}}

By October, Axis powers had achieved [[operational objective]]s in Ukraine and the Baltic region, with only the sieges of [[siege of Leningrad|Leningrad]]{{sfn|Kleinfeld|1983}}<!--please, don't add "page needed" template: it is a journal article--> and [[Siege of Sevastopol (1941–1942)|Sevastopol]] continuing.{{sfn|Jukes|2001|p=113}} A major [[Battle of Moscow|offensive against Moscow]] was renewed; after two months of fierce battles in increasingly harsh weather, the German army almost reached the outer suburbs of Moscow, where the exhausted troops<ref>{{Harvnb|Glantz|2001|p=26}}: "By 1 November [the Wehrmacht] had lost fully 20% of its committed strength (686,000 men), up to 2/3 of its ½&nbsp;million motor vehicles, and 65 percent of its tanks. The German Army High Command (OKH) rated its 136 divisions as equivalent to 83 full-strength divisions."</ref> were forced to suspend the offensive.{{sfn|Reinhardt|1992|p=227}} Large territorial gains were made by Axis forces, but their campaign had failed to achieve its main objectives: two key cities remained in Soviet hands, the Soviet [[Military capability|capability to resist]] was not broken, and the Soviet Union retained a considerable part of its military potential. The ''blitzkrieg'' [[Phase (combat)|phase]] of the war in Europe had ended.{{sfn|Milward|1964}}<!--please, don't add "page needed" template: it is a journal article-->

By early December, freshly mobilised [[Military reserve force|reserves]]{{sfn|Rotundo|1986}}<!--please, don't add "page needed" template: it is a journal article--> allowed the Soviets to achieve numerical parity with Axis troops.{{sfn|Glantz|2001|p=26}} This, as well as [[Richard Sorge#Wartime intelligence|intelligence data]] which established that a minimal number of Soviet troops in the East would be sufficient to deter any attack by the Japanese [[Kwantung Army]],<ref>{{Cite book|title=Blood, Tears and Folly|last=Deighton|first=Len|publisher=Pimlico|year=1993|isbn=978-0-7126-6226-0|location=London|page=[https://archive.org/details/bloodtearsfollyo0000deig_v3m3/page/479 479]|url=https://archive.org/details/bloodtearsfollyo0000deig_v3m3}}</ref> allowed the Soviets to begin a [[Winter campaign of 1941–1942|massive counter-offensive]] that started on 5 December all along the front and pushed German troops {{convert|100|-|250|km|mi}} west.<ref>{{Harvnb|Beevor|1998|pp=41–42}}; {{Harvnb|Evans|2008|pp=213–214}}, notes that "Zhukov had pushed the Germans back where they had launched Operation Typhoon two months before.&nbsp;... Only Stalin's decision to attack all along the front instead of concentrating his forces in an all-out assault against the retreating German Army Group Centre prevented the disaster from being even worse."</ref>

====War breaks out in the Pacific (1941)====
{{main|Pacific War}}
[[File:228 regiment in HK.jpg|thumb|left|Japanese soldiers [[Battle of Hong Kong|entering Hong Kong]], 8 December 1941]]

Following the Japanese [[false flag]] [[Mukden incident]] in 1931, the Japanese shelling of the American [[USS Panay incident|gunboat ''USS Panay'']] in 1937, and the 1937–1938 [[Nanjing Massacre]], [[Japan–United States relations#1937–1941|Japanese-American relations deteriorated]]. In 1939, the United States notified Japan that it would not be extending its trade treaty and American public opinion opposing Japanese expansionism led to a series of economic sanctions—the [[Export Control Act]]s—which banned U.S. exports of chemicals, minerals and military parts to Japan, and increased economic pressure on the Japanese regime.{{r|ibiblio_1940}}<ref>{{cite journal |year=1983 |title=Peace and War: United States Foreign Policy, 1931–1941 |journal=U.S. Department of State Publication |issue=1983 |pages=87–97 |url=https://www.ibiblio.org/pha/paw/ |access-date=17 February 2022 |archive-date=14 January 2022 |archive-url=https://web.archive.org/web/20220114073007/http://www.ibiblio.org/pha/paw/ |url-status=live }}</ref><ref name="ReferenceC">Maechling, Charles. ''Pearl Harbor: The First Energy War''. History Today. December 2000</ref> During 1939 Japan launched its [[Battle of Changsha (1939)|first attack against Changsha]], but was repulsed by late September.{{sfn|Jowett|Andrew|2002|p=14}} Despite [[1939–1940 Winter Offensive|several offensives]] by both sides, by 1940 the war between China and Japan was at a stalemate. To increase pressure on China by blocking supply routes, and to better position Japanese forces in the event of a war with the Western powers, Japan invaded and [[Japanese invasion of French Indochina|occupied northern Indochina]] in September 1940.{{sfn|Overy|Wheatcroft|1999|p=289}}

Chinese nationalist forces launched a large-scale [[1939–1940 Winter Offensive|counter-offensive]] in early 1940. In August, [[Chinese Communist Party|Chinese communists]] launched an [[Hundred Regiments Offensive|offensive in Central China]]; in retaliation, Japan instituted [[Three Alls policy|harsh measures]] in occupied areas to reduce human and material resources for the communists.{{sfn|Joes|2004|p=224}} Continued antipathy between Chinese communist and nationalist forces [[New Fourth Army incident|culminated in armed clashes in January 1941]], effectively ending their co-operation.{{sfn|Fairbank|Goldman|2006|p=320}} In March, the Japanese 11th army attacked the headquarters of the Chinese 19th army but was repulsed during [[Battle of Shanggao]].{{sfn|Hsu|Chang|1971|p=30}} In September, Japan attempted to [[Battle of Changsha (1941)|take the city of Changsha]] again and clashed with Chinese nationalist forces.{{sfn|Hsu|Chang|1971|p=33}}

German successes in Europe prompted Japan to increase pressure on European governments in [[Southeast Asia]]. The Dutch government agreed to provide Japan with oil supplies from the [[Dutch East Indies]], but negotiations for additional access to their resources ended in failure in June 1941.<ref>{{cite web |title=Japanese Policy and Strategy 1931 – July 1941 |website=US Army in WWII – Strategy and Command: The First Two Years |pages=45–66 |url=https://www.ibiblio.org/hyperwar/USA/USA-P-Strategy/Strategy-2.html |access-date=15 May 2013 |archive-url=https://web.archive.org/web/20130106021700/https://www.ibiblio.org/hyperwar/USA/USA-P-Strategy/Strategy-2.html |archive-date=6 January 2013 |url-status=live}}</ref> In July 1941 Japan sent troops to southern Indochina, thus threatening British and Dutch possessions in the Far East. The United States, the United Kingdom, and other Western governments reacted to this move with a freeze on Japanese assets and a total oil embargo.{{sfn|Anderson|1975|p=201}}{{sfn|Evans|Peattie|2012|p=456}} At the same time, Japan was [[Kantokuen|planning an invasion of the Soviet Far East]], intending to take advantage of the German invasion in the west, but abandoned the operation after the sanctions.<ref>{{cite book|last1=Coox|first1=Alvin|title=Nomonhan: Japan against Russia, 1939|date=1985|publisher=Stanford University Press|location=Stanford, CA|pages=1046–1049|isbn=978-0-8047-1835-6}}</ref>

Since early 1941, the United States and Japan had been engaged in negotiations in an attempt to improve their strained relations and end the war in China. During these negotiations, Japan advanced a number of proposals which were dismissed by the Americans as inadequate.<ref name=USAWWIIcp5>{{cite web |title=The decision for War |website=US Army in WWII – Strategy, and Command: The First Two Years |pages=113–127 |url=https://www.ibiblio.org/hyperwar/USA/USA-P-Strategy/Strategy-5.html |access-date=15 May 2013 |archive-url=https://web.archive.org/web/20130525064812/https://www.ibiblio.org/hyperwar/USA/USA-P-Strategy/Strategy-5.html |archive-date=25 May 2013 |url-status=live}}</ref> At the same time the United States, the United Kingdom, and the Netherlands engaged in secret discussions for the joint defence of their territories, in the event of a Japanese attack against any of them.<ref name=USAWWIIcp4>{{cite web |title=The Showdown With Japan Aug–Dec 1941 |website=US Army in WWII – Strategic Planning for Coalition Warfare |pages=63–96 |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-4.html |access-date=15 May 2013 |archive-url=https://web.archive.org/web/20121109144920/https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-4.html |archive-date=9 November 2012 |url-status=live}}</ref> Roosevelt reinforced [[Commonwealth of the Philippines|the Philippines (an American protectorate scheduled for independence in 1946)]] and warned Japan that the United States would react to Japanese attacks against any "neighboring countries".{{r|USAWWIIcp4}}

[[File:The USS Arizona (BB-39) burning after the Japanese attack on Pearl Harbor - NARA 195617 - Edit.jpg|thumb|right|The {{USS|Arizona|BB-39|6}} was a total loss in the [[Attack on Pearl Harbor|Japanese surprise air attack]] on the [[United States Pacific Fleet|American Pacific Fleet]] at [[Pearl Harbor]], Sunday 7 December 1941.]]
Frustrated at the lack of progress and feeling the pinch of the American–British–Dutch sanctions, Japan prepared for war. Emperor [[Hirohito]], after initial hesitation about Japan's chances of victory,<ref>{{cite book|last = Bix  | first = Herbert P.| author-link = Herbert P. Bix | date = 3 November 2016 | title = Hirohito and the making of modern Japan | publisher = HarperPerennial | isbn = 978-0-06-256051-3 | pages = 399–414}}</ref> began to favour Japan's entry into the war.<ref>{{cite journal |url=https://www.asahi.com/ajw/articles/14496398 |journal=The Asahi Shimbun |first=Ryuichi |last=Kitano |title=Diary: Hirohito prepared for U.S. war before Pearl Harbor attack |date=6 December 2021 |access-date=8 June 2022 |archive-date=17 April 2022 |archive-url=https://web.archive.org/web/20220417192302/https://www.asahi.com/ajw/articles/14496398 |url-status=live }}</ref> As a result, Prime Minister [[Fumimaro Konoe]] resigned.<ref>{{cite book | last = Fujiwara | first = Akira | date = 1991 | title = Shōwa tennō no jūgo-nen sensō | page = 126, citing Kenji Tomita's diary}}</ref><ref>Bix, ''Hirohito and the Making of Modern Japan'', pp. 417–420</ref> Hirohito refused the recommendation to appoint [[Prince Naruhiko Higashikuni]] in his place, choosing War Minister [[Hideki Tojo]] instead.<ref>Bix, ''Hirohito and the Making of Modern Japan'', p. 418</ref> On 3 November, Nagano explained in detail the plan of the [[attack on Pearl Harbor]] to the Emperor.<ref>{{cite book | last = Wetzler | first = Peter | date = 1998 | title = Hirohito and War: Imperial Tradition and Military Decision Making in Prewar Japan | publisher = University of Hawai'i Press | isbn = 978-0-8248-1925-5 | pages = 29, 35 | url = https://books.google.com/books?id=BWqEkwH1KRMC&pg=PA29 | access-date = 15 January 2024 | archive-date = 15 March 2024 | archive-url = https://web.archive.org/web/20240315182053/https://books.google.com/books?id=BWqEkwH1KRMC&pg=PA29 | url-status = live }}</ref> On 5 November, Hirohito approved in imperial conference the operations plan for the war.<ref>Bix, ''Hirohito and the Making of Modern Japan'', p. 424</ref> On 20 November, the new government presented an interim proposal as its final offer. It called for the end of American aid to China and for lifting the embargo on the supply of oil and other resources to Japan. In exchange, Japan promised not to launch any attacks in Southeast Asia and to withdraw its forces from southern Indochina.{{r|USAWWIIcp5}} The American counter-proposal of 26 November required that Japan evacuate all of China without conditions and conclude non-aggression pacts with all Pacific powers.<ref>[https://www.ibiblio.org/pha/pha/congress/app-d.html#363 The United States Replies] {{Webarchive|url=https://web.archive.org/web/20130429222741/https://www.ibiblio.org/pha/pha/congress/app-d.html#363 |date=29 April 2013 }}. Investigation of the Pearl Harbor attack.</ref> That meant Japan was essentially forced to choose between abandoning its ambitions in China, or seizing the natural resources it needed in the Dutch East Indies by force;<ref>{{Harvnb|Painter|2012|p=26}}: "The United States cut off oil exports to Japan in the summer of 1941, forcing Japanese leaders to choose between going to war to seize the oil fields of the Netherlands East Indies or giving in to U.S. pressure."</ref><ref>{{Harvnb|Wood|2007|p=9}}, listing various military and diplomatic developments, observes that "the threat to Japan was not purely economic."</ref> the Japanese military did not consider the former an option, and many officers considered the oil embargo an unspoken declaration of war.{{sfn|Lightbody|2004|p=125}}

Japan planned to seize European colonies in Asia to create a large defensive perimeter stretching into the Central Pacific. The Japanese would then be free to exploit the resources of Southeast Asia while exhausting the over-stretched Allies by fighting a defensive war.<ref>{{Harvnb|Weinberg|2005|p=310}}</ref><ref>{{Harvnb|Dower|1986|p=5}}, calls attention to the fact that "the Allied struggle against Japan exposed the racist underpinnings of the European and American colonial structure. Japan did not invade independent countries in southern Asia. It invaded colonial outposts which the Westerners had dominated for generations, taking absolutely for granted their racial and cultural superiority over their Asian subjects." Dower goes on to note that, before the horrors of Japanese occupation made themselves felt, many Asians responded favourably to the victories of the Imperial Japanese forces.</ref> To prevent American intervention while securing the perimeter, it was further planned to neutralise the [[United States Pacific Fleet]] and the American military presence in the Philippines from the outset.{{sfn|Wood|2007|pp=11–12}} On 7 December 1941 (8 December in Asian time zones), Japan attacked British and American holdings with near-simultaneous [[Japanese expansion (1941–42)|offensives against Southeast Asia and the Central Pacific]].{{sfn|Wohlstetter|1962|pp=341–343}} These included an [[Attack on Pearl Harbor|attack on the American fleets at Pearl Harbor]] and [[Philippines campaign (1941–1942)|the Philippines]], as well as invasions of [[Battle of Guam (1941)|Guam]], [[Battle of Wake Island|Wake Island]], [[Malayan campaign|Malaya]],{{sfn|Wohlstetter|1962|pp=341–343}} [[Japanese invasion of Thailand|Thailand]], and [[Battle of Hong Kong|Hong Kong]].<ref>[[John Keegan|Keegan, John]] (1989) ''The Second World War''. New York: Viking. pp. 256–257. {{isbn|978-0399504341}}</ref>

These attacks led the [[United States declaration of war on Japan|United States]], [[United Kingdom declaration of war on Japan|United Kingdom]], China, Australia, and several other states to formally declare war on Japan, whereas the Soviet Union, being heavily involved in large-scale hostilities with European Axis countries, maintained its neutrality agreement with Japan.<ref>{{Harvnb|Dunn|1998|p=157}}. According to {{Harvnb|May|1955|p=155}}, Churchill stated: "Russian declaration of war on Japan would be greatly to our advantage, provided, but only provided, that Russians are confident that will not impair their Western Front."</ref> Germany, followed by the other Axis states, declared war on the United States<ref>[[s:Adolf Hitler's Declaration of War against the United States|Adolf Hitler's Declaration of War against the United States]] in Wikisource.</ref> in solidarity with Japan, citing as justification the American attacks on German war vessels that had been ordered by Roosevelt.{{r|Events1941}}<ref>{{citation |last1=Klooz |first1=Marle |last2=Wiley |first2=Evelyn |others=Director: Humphrey, Richard A. |year=1944 |title=Events leading up to World War II – Chronological History |series=78th Congress, 2d Session – House Document N. 541 |location=Washington, DC |publisher=US Government Printing Office |at=p. 310 ([https://www.ibiblio.org/pha/events/1941.html 1941]) |url=https://www.ibiblio.org/pha/events/ |access-date=9 May 2013 |archive-url=https://web.archive.org/web/20131214113907/https://www.ibiblio.org/pha/events/ |archive-date=14 December 2013 |url-status=live}}</ref>

====Axis advance stalls (1942–1943)====
On 1 January 1942, the [[Four Policemen|Allied Big Four]]{{sfn|Bosworth|Maiolo|2015|pp=313–314}}—the Soviet Union, China, the United Kingdom, and the United States—and 22 smaller or exiled governments issued the [[Declaration by United Nations]], thereby affirming the [[Atlantic Charter]]{{sfn|Mingst|Karns|2007|p=22}} and agreeing not to sign a [[separate peace]] with the Axis powers.{{sfn|Shirer|1990|p=904}}

During 1942, Allied officials debated on the appropriate [[grand strategy]] to pursue. All agreed that [[Europe first|defeating Germany]] was the primary objective. The Americans favoured a straightforward, [[Operation Sledgehammer|large-scale attack]] on Germany through France. The Soviets demanded a second front. The British argued that military operations should target peripheral areas to wear out German strength, leading to increasing demoralisation, and bolstering resistance forces; Germany itself would be subject to a heavy bombing campaign. An offensive against Germany would then be launched primarily by Allied armour, without using large-scale armies.<ref>{{cite web |title=The First Full Dress Debate over Strategic Deployment. Dec 1941 – Jan 1942 |website=US Army in WWII – Strategic Planning for Coalition Warfare |pages=97–119 |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-5.html |access-date=16 May 2013 |archive-url=https://web.archive.org/web/20121109145033/https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-5.html |archive-date=9 November 2012 |url-status=live}}</ref> Eventually, the British persuaded the Americans that a landing in France was infeasible in 1942 and they should instead focus on driving the Axis out of North Africa.<ref>{{cite web |title=The Elimination of the Alternatives. Jul–Aug 1942 |website=US Army in WWII – Strategic Planning for Coalition Warfare |pages=266–292 |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-12.html |access-date=16 May 2013 |archive-url=https://web.archive.org/web/20130430013447/https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic1/USA-WD-Strategic1-12.html |archive-date=30 April 2013 |url-status=live}}</ref>

At the [[Casablanca Conference]] in early 1943, the Allies reiterated the statements issued in the 1942 Declaration and demanded the [[unconditional surrender]] of their enemies. The British and Americans agreed to continue to press the initiative in the Mediterranean by invading Sicily to fully secure the Mediterranean supply routes.<ref>{{cite web |title=Casablanca – Beginning of an Era: January 1943 |website=US Army in WWII – Strategic Planning for Coalition Warfare |pages=18–42 |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic2/USA-WD-Strategic2-1.html |access-date=16 May 2013 |archive-url=https://web.archive.org/web/20130525075310/https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic2/USA-WD-Strategic2-1.html |archive-date=25 May 2013 |url-status=live}}</ref> Although the British argued for further operations in the Balkans to bring Turkey into the war, in May 1943, the Americans extracted a British commitment to limit Allied operations in the Mediterranean to an invasion of the Italian mainland, and to invade France in 1944.<ref>{{cite web |title=The Trident Conference – New Patterns: May 1943 |website=US Army in WWII – Strategic Planning for Coalition Warfare |pages=126–145 |url=https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic2/USA-WD-Strategic2-6.html |access-date=16 May 2013 |archive-url=https://web.archive.org/web/20130525100621/https://www.ibiblio.org/hyperwar/USA/USA-WD-Strategic2/USA-WD-Strategic2-6.html |archive-date=25 May 2013 |url-status=live}}</ref>

=====Pacific (1942–1943)=====
[[File:Second world war asia 1937-1942 map en6.png|thumb|upright=1.4|Map of Japanese military advances through mid-1942]]

By the end of April 1942, Japan and its ally [[Thailand in World War II|Thailand]] had almost conquered [[Japanese invasion of Burma|Burma]], [[Malayan campaign|Malaya]], [[Dutch East Indies campaign|the Dutch East Indies]], [[Fall of Singapore|Singapore]], and [[Battle of Rabaul (1942)|Rabaul]], inflicting severe losses on Allied troops and taking a large number of prisoners.{{sfn|Beevor|2012|pp=247–267, 345}} Despite stubborn [[Philippines campaign (1941–1942)|resistance by Filipino and U.S. forces]], the [[Commonwealth of the Philippines|Philippine Commonwealth]] was eventually captured in May 1942, forcing its government into exile.{{sfn|Lewis|1953|loc=p. 529 (Table 11)}} On 16 April, in Burma, 7,000 British soldiers were encircled by the Japanese 33rd Division during the [[Battle of Yenangyaung]] and rescued by the Chinese 38th Division.{{sfn|Slim|1956|pp=71–74}} Japanese forces also achieved naval victories in the [[Sinking of Prince of Wales and Repulse|South China Sea]], [[Battle of the Java Sea|Java Sea]], and [[Indian Ocean raid|Indian Ocean]],{{sfn|Grove|1995|p=362}} and [[Bombing of Darwin|bombed the Allied naval base]] at [[Darwin, Northern Territory|Darwin]], Australia. In January 1942, the only Allied success against Japan was a Chinese [[Battle of Changsha (1941–1942)|victory at Changsha]].{{sfn|Ch'i|1992|p=158}} These easy victories over the unprepared U.S. and European opponents left Japan overconfident, and overextended.{{sfn|Perez|1998|p=145}}

In early May 1942, Japan initiated operations to [[Operation Mo|capture Port Moresby]] by [[amphibious warfare|amphibious assault]] and thus sever communications and supply lines between the United States and Australia. The planned invasion was thwarted when an Allied task force, centred on two American fleet carriers, fought Japanese naval forces to a draw in the [[Battle of the Coral Sea]].{{sfn|Maddox|1992|pp=111–112}} Japan's next plan, motivated by the earlier [[Doolittle Raid]], was to seize [[Midway Atoll]] and lure American carriers into battle to be eliminated; as a diversion, Japan would also send forces to [[Aleutian Islands campaign|occupy the Aleutian Islands]] in Alaska.{{sfn|Salecker|2001|p=186}} In mid-May, Japan started the [[Zhejiang-Jiangxi campaign]] in China, with the goal of inflicting retribution on the Chinese who aided the surviving American airmen in the Doolittle Raid by destroying Chinese air bases and fighting against the Chinese 23rd and 32nd Army Groups.<ref>{{Harvnb|Schoppa|2011|p=28}}.</ref><ref>[{{GBurl|id=lILltXBTo8oC|p=19}} Chevrier & Chomiczewski & Garrigue 2004], p. 19.</ref> In early June, Japan put its operations into action, but the Americans had broken [[Japanese naval codes]] in late May and were fully aware of the plans and order of battle, and used this knowledge to achieve a decisive [[Battle of Midway|victory at Midway]] over the [[Imperial Japanese Navy]].<ref>{{Harvnb|Ropp|2000|p=368}}.</ref>

With its capacity for aggressive action greatly diminished as a result of the Midway battle, Japan attempted to capture [[Port Moresby]] by an [[Kokoda Track campaign|overland campaign]] in the [[Territory of Papua]].{{sfn|Weinberg|2005|p=339}} The Americans planned a counterattack against Japanese positions in the southern [[Solomon Islands]], primarily [[Guadalcanal]], as a first step towards capturing [[Rabaul]], the main Japanese base in Southeast Asia.<ref>{{Cite book |last=Gilbert |first=Adrian |year=2003 |title=The Encyclopedia of Warfare: From Earliest Times to the Present Day |publisher=Globe Pequot |isbn=978-1-59228-027-8 |page=[https://archive.org/details/encyclopediaofwa0000gilb/page/259 259] |url=https://archive.org/details/encyclopediaofwa0000gilb/page/259 |access-date=26 June 2019 |archive-url=https://web.archive.org/web/20190719123035/https://archive.org/details/encyclopediaofwa0000gilb/page/259 |archive-date=19 July 2019 |url-status=live }}</ref>

Both plans started in July, but by mid-September, [[Guadalcanal campaign|the Battle for Guadalcanal]] took priority for the Japanese, and troops in New Guinea were ordered to withdraw from the Port Moresby area to the [[Oro Province|northern part of the island]], where they faced Australian and United States troops in the [[Battle of Buna–Gona]].{{sfn|Swain|2001|p=197}} Guadalcanal soon became a focal point for both sides with heavy commitments of troops and ships in the battle for Guadalcanal. By the start of 1943, the Japanese were defeated on the island and [[Operation Ke|withdrew their troops]].{{sfn|Hane|2001|p=340}} In Burma, Commonwealth forces mounted two operations. The first was a disastrous [[Arakan campaign (1942–1943)|offensive into the Arakan region]] in late 1942 that forced a retreat back to India by May 1943.{{sfn|Marston|2005|p=111}} The second was the [[Operation Longcloth|insertion of irregular forces]] behind Japanese frontlines in February which, by the end of April, had achieved mixed results.{{sfn|Brayley|2002|p=9}}

=====Eastern Front (1942–1943)=====
[[File:RIAN archive 44732 Soviet soldiers attack house.jpg|thumb|upright=1.5|[[Red Army]] soldiers on the counterattack during the [[Battle of Stalingrad]], February 1943]]

Despite considerable losses, in early 1942 Germany and its allies stopped a major Soviet offensive in [[Central Russia|central]] and [[southern Russia]], keeping most territorial gains they had achieved during the previous year.{{sfn|Glantz|2001|p=31}} In May, the Germans defeated Soviet offensives in the [[Battle of the Kerch Peninsula|Kerch Peninsula]] and at [[Second Battle of Kharkov|Kharkov]],{{sfn|Read|2004|p=764}} and then in June 1942 launched their main [[Case Blue|summer offensive]] against southern Russia, to seize the [[Petroleum industry in Azerbaijan|oil fields of the Caucasus]] and occupy the [[Kuban]] [[steppe]], while maintaining positions on the northern and central areas of the front. The Germans split [[Army Group South]] into two groups: [[Army Group A]] advanced to the lower [[Don (river)|Don River]] and struck south-east to the Caucasus, while [[Army Group B]] headed towards the [[Volga|Volga River]]. The Soviets decided to make their stand at Stalingrad on the Volga.{{sfn|Davies|2006|loc=p. 100 (2008 ed.)}}

By mid-November, the Germans had [[Battle of Stalingrad|nearly taken Stalingrad]] in bitter [[urban warfare|street fighting]]. The Soviets began their second winter counter-offensive, starting with an [[Operation Uranus|encirclement of German forces at Stalingrad]],{{sfn|Beevor|1998|pp=239–265}} and an assault on the [[Operation Mars|Rzhev salient near Moscow]], though the latter failed disastrously.{{sfn|Black|2003|p=119}} By early February 1943, the German Army had taken tremendous losses; German troops at Stalingrad had been defeated,{{sfn|Beevor|1998|pp=383–391}} and the front-line had been pushed back beyond its position before the summer offensive. In mid-February, after the Soviet push had tapered off, the Germans launched another [[Third Battle of Kharkov|attack on Kharkov]], creating a [[Salient (military)|salient]] in their front line around the Soviet city of [[Kursk]].{{sfn|Erickson|2001|p=142}}

=====Western Europe/Atlantic and Mediterranean (1942–1943)=====
[[File:8th AF Bombing Marienburg.JPEG|right|thumb|American [[Eighth Air Force]] [[Boeing B-17 Flying Fortress]] bombing raid on the Focke-Wulf factory in Germany, 9 October 1943]]

Exploiting poor American naval command decisions, [[Second Happy Time|the German navy ravaged Allied shipping off the American Atlantic coast]].{{sfn|Milner|1990|p=52}} By November 1941, Commonwealth forces had launched a counter-offensive in North Africa, [[Operation Crusader]], and reclaimed all the gains the Germans and Italians had made.{{sfn|Beevor|2012|pp=224–228}} The Germans also launched a North African offensive in January, pushing the British back to positions at the [[Battle of Gazala#Gazala line|Gazala line]] by early February,{{sfn|Molinari|2007|p=91}} followed by a temporary lull in combat which Germany used to prepare for their upcoming offensives.{{sfn|Mitcham|2007|p=31}} Concerns that the Japanese might use bases in [[French Madagascar|Vichy-held Madagascar]] caused the British to [[Battle of Madagascar|invade the island]] in early May 1942.{{sfn|Beevor|2012|pp=380–381}} An Axis [[Battle of Gazala|offensive in Libya]] forced an Allied retreat deep inside Egypt until Axis forces were [[First Battle of El Alamein|stopped at El Alamein]].{{sfn|Rich|1992|p=178}} On the Continent, raids of Allied [[commando]]s on strategic targets, culminating in the failed [[Dieppe Raid]],{{sfn|Gordon|2004|p=129}} demonstrated the Western Allies' inability to launch an invasion of continental Europe without much better preparation, equipment, and operational security.{{sfn|Neillands|2005|p=60}}

In August 1942, the Allies succeeded in repelling a [[Battle of Alam el Halfa|second attack against El Alamein]]{{sfn|Keegan|1997|p=277}} and, at a high cost, managed to [[Operation Pedestal|deliver desperately needed supplies to the besieged Malta]].{{sfn|Smith|2002}} A few months later, the Allies [[Second Battle of El Alamein|commenced an attack of their own]] in Egypt, dislodging the Axis forces and beginning a drive west across Libya.{{sfn|Thomas|Andrew|1998|p=8}} This attack was followed up shortly after by [[Operation Torch|Anglo-American landings in French North Africa]], which resulted in the region joining the Allies.{{sfn|Ross|1997|p=38}} Hitler responded to the French colony's defection by ordering the [[Case Anton|occupation of Vichy France]];{{sfn|Ross|1997|p=38}} although Vichy forces did not resist this violation of the armistice, they managed to [[Scuttling of the French fleet at Toulon|scuttle their fleet]] to prevent its capture by German forces.{{sfn|Ross|1997|p=38}}{{sfn|Bonner|Bonner|2001|p=24}} Axis forces in Africa withdrew into [[Tunisia]], which was [[Tunisian campaign|conquered by the Allies]] in May 1943.{{sfn|Ross|1997|p=38}}{{sfn|Collier|2003|p=11}}

In June 1943, the British and Americans began [[Combined Bomber Offensive|a strategic bombing campaign]] against Germany with a goal to disrupt the war economy, reduce morale, and "[[Dehousing|de-house]]" the civilian population.<ref>[https://www.ibiblio.org/hyperwar/AAF/USSBS/ETO-Summary.html#tc "The Civilians"] {{Webarchive|url=https://web.archive.org/web/20131105044932/https://www.ibiblio.org/hyperwar/AAF/USSBS/ETO-Summary.html#tc |date=5 November 2013 }} the United States Strategic Bombing Survey Summary Report (European War)</ref> The [[Bombing of Hamburg in World War II|firebombing of Hamburg]] was among the first attacks in this campaign, inflicting significant casualties and considerable losses on infrastructure of this important industrial centre.{{sfn|Overy|1995|pp=119–120}}

====Allies gain momentum (1943–1944)====
[[File:SBD VB-16 over USS Washington 1943.jpg|thumb|left|[[United States Navy|U.S. Navy]] [[Douglas SBD Dauntless|SBD-5]] [[scout plane]] flying patrol over {{USS|Washington|BB-56|6}} and {{USS|Lexington|CV-16|6}} during the [[Gilbert and Marshall Islands campaign]], 1943]]

After the Guadalcanal campaign, the Allies initiated several operations against Japan in the Pacific. In May 1943, Canadian and U.S. forces were sent to [[Aleutian Islands campaign#Allied response|eliminate Japanese forces from the Aleutians]].{{sfn|Thompson|Randall|2008|p=164}} Soon after, the United States, with support from Australia, New Zealand and Pacific Islander forces, began major ground, sea and air operations to [[Operation Cartwheel|isolate Rabaul by capturing surrounding islands]], and [[Gilbert and Marshall Islands campaign|breach the Japanese Central Pacific perimeter at the Gilbert and Marshall Islands]].{{sfn|Kennedy|2001|p=610}} By the end of March 1944, the Allies had completed both of these objectives and had also [[Operation Hailstone|neutralised the major Japanese base at Truk]] in the [[Caroline Islands]]. In April, the Allies launched an operation to [[Western New Guinea campaign|retake Western New Guinea]].{{sfn|Rottman|2002|p=228}}

In the Soviet Union, both the Germans and the Soviets spent the spring and early summer of 1943 preparing for large offensives in [[central Russia]]. On 5 July 1943, Germany [[Battle of Kursk|attacked Soviet forces around the Kursk Bulge]]. Within a week, German forces had exhausted themselves against the Soviets' well-constructed defences,<ref>{{Harvnb|Glantz|1986}}; {{Harvnb|Glantz|1989|pp=149–159}}.</ref> and for the first time in the war, Hitler cancelled an operation before it had achieved tactical or operational success.{{sfn|Kershaw|2001|p=592}} This decision was partially affected by the Western Allies' [[Allied invasion of Sicily|invasion of Sicily]] launched on 9 July, which, combined with previous Italian failures, resulted in the [[Fall of the Fascist regime in Italy|ousting and arrest of Mussolini]] later that month.{{sfn|O'Reilly|2001|p=32}}

On 12 July 1943, the Soviets launched their own [[Operation Kutuzov|counter-offensives]], thereby dispelling any chance of German victory or even stalemate in the east. The Soviet victory at Kursk marked the end of German superiority,{{sfn|Bellamy|2007|p=595}} giving the Soviet Union the initiative on the Eastern Front.{{sfn|O'Reilly|2001|p=35}}{{sfn|Healy|1992|p=90}} The Germans tried to stabilise their eastern front along the hastily fortified [[Panther–Wotan line]], but the Soviets broke through it at [[Smolensk operation|Smolensk]] and the [[Battle of the Dnieper|Lower Dnieper Offensive]].{{sfn|Glantz|2001|pp=50–55}}

On 3 September 1943, the Western Allies [[Allied invasion of Italy|invaded the Italian mainland]], following [[Armistice of Cassibile|Italy's armistice with the Allies]] and the ensuing German occupation of Italy.<ref>{{Harvnb|Kolko|1990|p=45}}</ref> Germany, with the help of fascists, responded to the armistice by [[Operation Achse|disarming Italian forces]] that were in many places without superior orders, seizing military control of Italian areas,{{sfn|Mazower|2008|p=362}} and creating a series of defensive lines.{{sfn|Hart|Hart|Hughes|2000|p=151}} German special forces then [[Gran Sasso raid|rescued Mussolini]], who then soon established a new client state in German-occupied Italy named the [[Italian Social Republic]],{{sfn|Blinkhorn|2006|p=52}} causing an [[Italian Civil War|Italian civil war]]. The Western Allies fought through several lines until reaching the [[Winter Line|main German defensive line]] in mid-November.{{sfn|Read|Fisher|2002|p=129}}

[[File:Soviet troops and T-34 tanks counterattacking Kursk Voronezh Front July 1943.jpg|thumb|[[Red Army]] troops in a counter-offensive on German positions at the [[Battle of Kursk]], July 1943]]

German operations in the Atlantic also suffered. By [[Black May (1943)|May 1943, as Allied counter-measures became increasingly effective]], the resulting sizeable German submarine losses forced a temporary halt of the German Atlantic naval campaign.<ref>{{Harvnb|Padfield|1998|pp=335–336}}.</ref> In November 1943, [[Franklin D. Roosevelt]] and Winston Churchill met with [[Chiang Kai-shek]] [[Cairo Conference|in Cairo]] and then with Joseph Stalin [[Tehran Conference|in Tehran]].<ref name="Kolko 1990 211,235,267_268">{{Harvnb|Kolko|1990|pp=211, 235, 267–268}}.</ref> The former conference determined the post-war return of Japanese territory<ref name="Iriye 1981 154">{{Harvnb|Iriye|1981|p=154}}.</ref> and the military planning for the [[Burma campaign]],{{sfn|Mitter|2014|p=286}} while the latter included agreement that the Western Allies would invade Europe in 1944 and that the Soviet Union would declare war on Japan within three months of Germany's defeat.<ref name="polley148">{{Harvnb|Polley|2000|p=148}}.</ref>

From November 1943, during the seven-week [[Battle of Changde]], the Chinese awaited allied relief as they forced Japan to fight a costly war of attrition.<ref name="Beevor 2012 268_274">{{Harvnb|Beevor|2012|pp=268–274}}.</ref><ref name=H161>{{Harvnb|Ch'i|1992|p=161}}.</ref><ref name="Hsu Chang 412-416">{{Harvnb|Hsu|Chang|1971|pp=412–416, Map 38}}</ref> In January 1944, the Allies launched a [[Battle of Monte Cassino|series of attacks in Italy against the line at Monte Cassino]] and tried to outflank it with [[Battle of Anzio|landings at Anzio]].<ref>{{Harvnb|Weinberg|2005|pp=660–661}}.</ref>

On 27 January 1944, [[Leningrad Front|Soviet]] troops launched [[Siege of Leningrad#Soviet relief of the siege|a major offensive]] that expelled German forces from the [[Leningrad Oblast|Leningrad region]], thereby ending the [[List of battles by casualties#Sieges and urban combat|most lethal siege in history]].<ref name="Glantz 2002 327_366">{{Harvnb|Glantz|2002|pp=327–366}}.</ref> The [[Leningrad–Novgorod offensive|following Soviet offensive]] was [[Battle of Narva (1944)|halted on the pre-war Estonian border]] by the German [[Army Group North]] aided by [[German occupation of Estonia during World War II#Estonians in Nazi German military units|Estonians]] hoping to [[Estonian government-in-exile#Failure to reestablish independence|re-establish national independence]]. This delay slowed subsequent Soviet operations in the [[Baltic Sea]] region.<ref name="Glantz 2002 367_414">{{Harvnb|Glantz|2002|pp=367–414}}.</ref> By late May 1944, the Soviets had [[Crimean offensive|liberated Crimea]], [[Dnieper–Carpathian offensive|largely expelled Axis forces from Ukraine]], and made [[First Jassy–Kishinev offensive|incursions into Romania]], which were repulsed by the Axis troops.<ref name="Chubarov 2001 122">{{Harvnb|Chubarov|2001|p=122}}.</ref> The Allied offensives in Italy had succeeded and, at the expense of allowing several German divisions to retreat, Rome was captured on June 4.<ref>{{Harvnb|Holland|2008|pp=169–184}}; {{Harvnb|Beevor|2012|pp=568–573}}.<br />The weeks after the fall of Rome saw a dramatic upswing in German atrocities in Italy ({{Harvnb|Mazower|2008|pp=500–502}}). The period featured massacres with victims in the hundreds at [[Civitella in Val di Chiana|Civitella]] ({{Harvnb|de Grazia|Paggi|1991}}; {{Harvnb|Belco|2010}}), [[Ardeatine massacre|Fosse Ardeatine]] ({{Harvnb|Portelli|2003}}), and [[Sant'Anna di Stazzema massacre|Sant'Anna di Stazzema]] ({{Harvnb|Gordon|2012|pp=10–11}}), and is capped with the [[Marzabotto massacre]].</ref>

The Allies had mixed success in mainland Asia. In March 1944, the Japanese launched the first of two invasions, [[Operation U-Go|an operation against Allied positions in Assam, India]],<ref name="Lightbody 2004 224">{{Harvnb|Lightbody|2004|p=224}}.</ref> and soon besieged Commonwealth positions at [[Battle of Imphal|Imphal]] and [[Battle of Kohima|Kohima]].<ref name="Zeiler">{{Harvnb|Zeiler|2004|p=60}}.</ref> In May 1944, British and Indian forces mounted a counter-offensive that drove Japanese troops back to Burma by July,<ref name="Zeiler" /> and Chinese forces that had [[Battle of Northern Burma and Western Yunnan|invaded northern Burma]] in late 1943 [[Siege of Myitkyina|besieged Japanese troops]] in [[Myitkyina]].<ref>{{Harvnb|Beevor|2012|pp=555–560}}.</ref> The [[Operation Ichi-Go|second Japanese invasion]] of China aimed to destroy China's main fighting forces, secure railways between Japanese-held territory and capture Allied airfields.<ref>{{Harvnb|Ch'i|1992|p=163}}.</ref> By June, the Japanese had conquered the province of [[Henan]] and begun a [[Battle of Changsha (1944)|new attack on Changsha]].<ref>{{Harvnb|Coble|2003|p=85}}.</ref>

====Allies close in (1944)====
[[File:Approaching Omaha.jpg|thumb|American troops approaching [[Omaha Beach]] during the [[Operation Overlord|invasion of Normandy]] on [[Normandy landings|D-Day]], 6 June 1944]]

On 6 June 1944 (commonly known as [[Normandy landings|D-Day]]), after three years of Soviet pressure,<ref name=rees406>{{Harvnb|Rees|2008|pp=406–407}}: "Stalin always believed that Britain and America were delaying the second front so that the Soviet Union would bear the brunt of the war."</ref> the Western Allies [[Operation Overlord|invaded northern France]]. After reassigning several Allied divisions from Italy, they also [[Operation Dragoon|attacked southern France]].<ref name="Weinberg 2005 695">{{Harvnb|Weinberg|2005|p=695}}.</ref> These landings were successful and led to the defeat of the [[Falaise pocket|German Army units in France]]. [[Paris]] was [[Liberation of Paris|liberated]] on 25 August by the [[French Resistance|local resistance]] assisted by the [[Free French Forces]], both led by General [[Charles de Gaulle]],<ref>{{Harvnb|Badsey|1990|p=91}}.</ref> and the Western Allies continued to [[Siegfried Line campaign|push back German forces]] in western Europe during the latter part of the year. An attempt to advance into northern Germany spearheaded by [[Operation Market Garden|a major airborne operation]] in the Netherlands failed.<ref>{{Harvnb|Dear|Foot|2001|p=562}}.</ref> After that, the Western Allies slowly pushed into Germany, but [[Operation Queen|failed to cross the Rur river]]. In Italy, the Allied advance slowed due to the [[Gothic Line|last major German defensive line]].<ref>{{Harvnb|Forrest|Evans|Gibbons|2012|p=191}}</ref>

On 22 June, the Soviets launched a strategic offensive in Belarus ("[[Operation Bagration]]") that nearly destroyed the German [[Army Group Centre]].<ref name="Zaloga 1996 7">{{Harvnb|Zaloga|1996|p=7}}: "It was the most calamitous defeat of all the German armed forces in World War II."</ref> Soon after that, [[Lvov–Sandomierz offensive|another Soviet strategic offensive]] forced German troops from Western Ukraine and Eastern Poland. The Soviets formed the [[Polish Committee of National Liberation]] to control territory in Poland and combat the Polish [[Home Army|Armia Krajowa]]; the Soviet Red Army remained in the [[Praga]] district on the other side of the [[Vistula]] and watched passively as the Germans quelled the [[Warsaw Uprising]] initiated by the Armia Krajowa.<ref>{{Harvnb|Berend|1996|p=8}}.</ref> The [[Slovak National Uprising|national uprising]] in [[Slovak Republic (1939–1945)|Slovakia]] was also quelled by the Germans.<ref>{{cite web|url=https://www.mzv.sk/documents/10182/2369491/BROZURA_70_VYROCIE_SNP_indd.pdf/007d0f33-4aa1-4e3a-95ae-5ef5096360d3|title=Slovak National Uprising 1944|publisher=Ministry of Foreign and European Affairs of the Slovak Republic|work=Museum of the Slovak National Uprising|access-date=27 April 2020|archive-date=19 May 2020|archive-url=https://web.archive.org/web/20200519024459/https://www.mzv.sk/documents/10182/2369491/BROZURA_70_VYROCIE_SNP_indd.pdf/007d0f33-4aa1-4e3a-95ae-5ef5096360d3|url-status=live}}</ref> The Soviet [[Red Army]]'s [[Second Jassy–Kishinev offensive|strategic offensive in eastern Romania]] cut off and destroyed the [[Army Group South Ukraine|considerable German troops there]] and triggered [[1944 Romanian coup d'état|a successful coup d'état in Romania]] and [[1944 Bulgarian coup d'état|in Bulgaria]], followed by those countries' shift to the Allied side.<ref name="countrystudies.us">{{cite web|url=https://countrystudies.us/romania/23.htm|title=Armistice Negotiations and Soviet Occupation|publisher=US Library of Congress|access-date=14 November 2009|quote=The coup speeded the Red Army's advance, and the Soviet Union later awarded Michael the Order of Victory for his courage in overthrowing Antonescu and putting an end to Romania's war against the Allies. Western historians uniformly point out that the Communists played only a supporting role in the coup; postwar Romanian historians, however, ascribe to the Communists the decisive role in Antonescu's overthrow|archive-url=https://web.archive.org/web/20110430001849/https://countrystudies.us/romania/23.htm|archive-date=30 April 2011|url-status=live}}</ref>

[[File:Douglas MacArthur lands Leyte1.jpg|thumb|left|[[General (United States)|General]] [[Douglas MacArthur]] returns to the [[Commonwealth of the Philippines|Philippines]] during the [[Battle of Leyte]], 20 October 1944]]

In September 1944, Soviet troops advanced into [[Democratic Federal Yugoslavia|Yugoslavia]] and forced the rapid withdrawal of German Army Groups [[Army Group E|E]] and [[Army Group F|F]] in [[Axis occupation of Greece|Greece]], [[German occupation of Albania|Albania]] and Yugoslavia to rescue them from being cut off.<ref name="Evans 2008 653">{{Harvnb|Evans|2008|p=653}}.</ref> By this point, the communist-led [[Yugoslav Partisans|Partisans]] under Marshal [[Josip Broz Tito]], who had led an [[World War II in Yugoslavia|increasingly successful guerrilla campaign]] against the occupation since 1941, controlled much of the territory of Yugoslavia and engaged in delaying efforts against German forces further south. In northern [[Territory of the Military Commander in Serbia|Serbia]], the Soviet [[Red Army]], with limited support from Bulgarian forces, assisted the Partisans in a joint [[Belgrade offensive|liberation of the capital city of Belgrade]] on 20 October. A few days later, the Soviets launched a [[Budapest offensive|massive assault]] against [[Operation Panzerfaust|German-occupied]] Hungary that lasted until [[Siege of Budapest|the fall of Budapest]] in February 1945.<ref>{{Harvnb|Wiest|Barbier|2002|pp=65–66}}.</ref> Unlike impressive Soviet victories in the Balkans, [[Continuation War|bitter Finnish resistance]] to the [[Vyborg–Petrozavodsk offensive|Soviet offensive]] in the [[Karelian Isthmus]] denied the Soviets occupation of Finland and led to a [[Moscow Armistice|Soviet-Finnish armistice]] on relatively mild conditions,<ref>{{Cite book|last=Wiktor|first=Christian L|title=Multilateral Treaty Calendar – 1648–1995|publisher=Kluwer Law International|year=1998|isbn=978-90-411-0584-4|page=426}}</ref> although Finland was forced to [[Lapland War|fight their former German allies]].{{sfn|Shirer|1990|p=1085}}

By the start of July 1944, Commonwealth forces in Southeast Asia had repelled the Japanese sieges in [[Assam]], pushing the Japanese back to the [[Chindwin River]]<ref name="Marston 2005 120">{{Harvnb|Marston|2005|p=120}}.</ref> while the Chinese captured Myitkyina. In September 1944, Chinese forces [[Battle of Mount Song|captured Mount Song]] and reopened the [[Burma Road]].<ref>{{cite web|url=https://www.china1931.cn/China/ShowArticle.asp?ArticleID%3D7648 |script-title=zh:全面抗战，战犯前仆后继见阎王 |trans-title=The war criminals tries to be the first to see their ancestors<!-- in source --> |language=zh |access-date=16 March 2013 |url-status=dead |archive-url=https://web.archive.org/web/20160303224203/https://www.china1931.cn/China/ShowArticle.asp?ArticleID=7648 |archive-date=3 March 2016 }}</ref> In China, the Japanese had more successes, having finally [[Battle of Changsha (1944)|captured Changsha]] in mid-June and the city of [[Battle of Hengyang|Hengyang]] by early August.<ref>{{Harvnb|Jowett|Andrew|2002|p=8}}.</ref> Soon after, they invaded the province of [[Guangxi]], winning major engagements against Chinese forces at [[Battle of Guilin–Liuzhou|Guilin and Liuzhou]] by the end of November<ref>{{Harvnb|Howard|2004|p=140}}.</ref> and successfully linking up their forces in China and Indochina by mid-December.<ref name="Drea 2003 54">{{Harvnb|Drea|2003|p=54}}.</ref>

In the Pacific, U.S. forces continued to push back the Japanese perimeter. In mid-June 1944, they began their [[Mariana and Palau Islands campaign|offensive against the Mariana and Palau islands]] and decisively defeated Japanese forces in the [[Battle of the Philippine Sea]]. These defeats led to the resignation of the Japanese Prime Minister, [[Hideki Tojo]], and provided the United States with air bases to launch intensive heavy bomber attacks on the Japanese home islands. In late October, American forces [[Battle of Leyte|invaded the Filipino island of Leyte]]; soon after, Allied naval forces scored another large victory in the [[Battle of Leyte Gulf]], one of the largest naval battles in history.<ref>{{Harvnb|Cook|Bewes|1997|p=305}}.</ref>

====Axis collapse and Allied victory (1944–1945)====
[[File:Yalta Conference (Churchill, Roosevelt, Stalin) (B&W).jpg|thumb|[[Yalta Conference]] held in February 1945, with [[Winston Churchill]], [[Franklin D. Roosevelt]], and [[Joseph Stalin]]]]

On 16 December 1944, Germany made a last attempt to split the Allies on the Western Front by using most of its remaining reserves to launch [[Battle of the Bulge|a massive counter-offensive in the Ardennes]] and [[Operation Northwind (1944)|along the French-German border]], hoping to encircle large portions of Western Allied troops and prompt a political settlement after capturing their primary supply port at [[Antwerp]]. By 16 January 1945, this offensive had been repulsed with no strategic objectives fulfilled.<ref name="parkerxiii">{{Harvnb|Parker|2004|pp=xiii–xiv, 6–8, 68–70, 329–330}}</ref> In Italy, the Western Allies remained stalemated at the German defensive line. In mid-January 1945, the Red Army attacked in Poland, [[Vistula–Oder offensive|pushing from the Vistula to the Oder]] river in Germany, and [[East Prussian offensive|overran East Prussia]].<ref>{{Harvnb|Glantz|2001|p=85}}.</ref> On 4 February Soviet, British, and U.S. leaders met for the [[Yalta Conference]]. They agreed on the occupation of post-war Germany, and on when the Soviet Union would join the war against Japan.<ref>{{Harvnb|Beevor|2012|pp=709–722}}.</ref>

In February, the Soviets [[Silesian offensives|entered Silesia]] and [[East Pomeranian offensive|Pomerania]], while the [[Western Allied invasion of Germany|Western Allies entered western Germany]] and closed to the [[Rhine]] river. By March, the Western Allies crossed the Rhine [[Operation Plunder|north]] and [[Remagen|south]] of the [[Ruhr (river)|Ruhr]], [[Ruhr pocket|encircling the German Army Group B]].<ref>{{Harvnb|Buchanan|2006|p=21}}.</ref> In early March, in an attempt to protect its last oil reserves in Hungary and retake Budapest, Germany launched [[Operation Spring Awakening|its last major offensive]] against Soviet troops near [[Lake Balaton]]. In two weeks, the offensive had been repulsed, the Soviets advanced to [[Vienna offensive|Vienna]], and captured the city. In early April, Soviet troops [[Battle of Königsberg|captured Königsberg]], while the Western Allies finally [[Spring 1945 offensive in Italy|pushed forward in Italy]] and swept across western Germany capturing [[Capture of Hamburg|Hamburg]] and [[Battle of Nuremberg (1945)|Nuremberg]]. [[Elbe Day|American and Soviet forces met at the Elbe river]] on 25 April, leaving unoccupied pockets in southern Germany and around Berlin.

Soviet troops [[Battle of Berlin|stormed and captured Berlin]] in late April.{{sfn|Kershaw|2001|pp=793–829}} In Italy, [[Surrender of Caserta|German forces surrendered]] on 29 April, while the [[Italian Social Republic]] capitulated two days later. On 30 April, the [[Reichstag building|Reichstag]] was captured, signalling the military defeat of Nazi Germany.<ref name="Shepardson 1998">{{Harvnb|Shepardson|1998}}</ref>

Major changes in leadership occurred on both sides during this period. On 12 April, President Roosevelt died and was succeeded by his vice president, [[Harry S. Truman]]. Benito Mussolini [[Death of Benito Mussolini|was killed]] by [[Italian resistance movement|Italian partisans]] on 28 April.<ref name="O'Reilly 2001 244">{{Harvnb|O'Reilly|2001|p=244}}.</ref> On 30 April, [[Death of Adolf Hitler|Hitler committed suicide]] in his [[Führerbunker|headquarters]], and was succeeded by [[Grand Admiral]] [[Karl Dönitz]] (as [[President of Germany (1919–1945)|President of the Reich]]) and [[Joseph Goebbels]] (as [[Chancellor of the Reich]]); Goebbels also committed suicide on the following day and was replaced by [[Lutz Graf Schwerin von Krosigk]], in what would later be known as the [[Flensburg Government]]. [[German Instrument of Surrender|Total and unconditional surrender]] in Europe was signed [[Victory in Europe Day|on 7{{nbsp}}and 8{{nbsp}}May]], to be effective by the end of [[Victory Day (9 May)|8 May]].<ref name="Evans 2008 737">{{Harvnb|Evans|2008|p=737}}.</ref> German Army Group Centre [[Prague offensive|resisted in Prague]] until 11 May.<ref name="Glantz 1998 34">{{Harvnb|Glantz|1998|p=24}}.</ref> On 23 May all remaining members of the German government were arrested by the Allied Forces in [[Flensburg]], while on 5 June all German political and military institutions were transferred under the control of the Allies through the [[Berlin Declaration (1945)|Berlin Declaration]].<ref>{{cite book |last1=Selby |first1=Scott A. |title=The Axmann Conspiracy: The Nazi Plan for a Fourth Reich and How the U.S. Army Defeated It |date=28 July 2021 |page=8 |publisher=Scott Andrew Selby |url=https://books.google.com/books?id=7SQ_EAAAQBAJ |access-date=4 March 2024 |language=en}}</ref>

In the Pacific theatre, American forces accompanied by the forces of the [[Commonwealth of the Philippines|Philippine Commonwealth]] advanced [[Philippines campaign (1944–1945)|in the Philippines]], [[Battle of Leyte|clearing Leyte]] by the end of April 1945. They [[Battle of Luzon|landed on Luzon]] in January 1945 and [[Battle of Manila (1945)|recaptured Manila]] in March. Fighting continued on Luzon, [[Battle of Mindanao|Mindanao]], and other islands of the Philippines until the [[End of World War II in Asia|end of the war]].<ref>{{Cite book|last=Chant|first=Christopher|year=1986|title=The Encyclopedia of Codenames of World War II|publisher=Routledge & Kegan Paul|page=118|isbn=978-0-7102-0718-0}}</ref> Meanwhile, the [[United States Army Air Forces]] launched [[Air raids on Japan|a massive firebombing campaign]] of strategic cities in Japan in an effort to destroy Japanese war industry and civilian morale. A devastating [[Bombing of Tokyo|bombing raid on Tokyo of 9–10 March]] was the deadliest conventional bombing raid in history.<ref>{{cite magazine|url=https://www.wired.com/2011/03/0309incendiary-bombs-kill-100000-tokyo/|title=March 9, 1945: Burning the Heart Out of the Enemy|last=Long|first=Tony|date=9 March 2011|magazine=Wired|publisher=Wired Magazine|access-date=22 June 2018|quote=1945: In the single deadliest air raid of World War II, 330 American B-29s rain incendiary bombs on Tokyo, touching off a firestorm that kills upwards of 100,000 people, burns a quarter of the city to the ground, and leaves a million homeless.|archive-url=https://web.archive.org/web/20170323180239/https://www.wired.com/2011/03/0309incendiary-bombs-kill-100000-tokyo/|archive-date=23 March 2017|url-status=live}}</ref>

[[File:Mamoru Shigemitsu signs the Instrument of Surrender, officially ending the Second World War.jpg|thumb|Japanese foreign affairs minister [[Mamoru Shigemitsu]] signs the [[Japanese Instrument of Surrender]] on board {{USS|Missouri|BB-63|6}}, 2 September 1945.]]

In May 1945, Australian troops [[Borneo campaign|landed in Borneo]], overrunning the oilfields there. British, American, and Chinese forces defeated the Japanese in northern [[Burma campaign|Burma]] in March, and the British pushed on to reach [[Yangon|Rangoon]] by 3 May.<ref name="Drea 2003 57">{{Harvnb|Drea|2003|p=57}}.</ref> Chinese forces started a counterattack in the [[Battle of West Hunan]] that occurred between 6 April and 7 June 1945. American naval and amphibious forces also moved towards Japan, taking [[Battle of Iwo Jima|Iwo Jima]] by March, and [[Battle of Okinawa|Okinawa]] by the end of June.<ref>{{Harvnb|Jowett|Andrew|2002|p=6}}.</ref> At the same time, a naval blockade by [[Allied submarines in the Pacific War|submarines]] was strangling Japan's economy and drastically reducing its ability to supply overseas forces.<ref name="results of german and american submarines">{{cite web|last=Poirier |first=Michel Thomas |title=Results of the German and American Submarine Campaigns of World War II |url=https://www.navy.mil/navydata/cno/n87/history/wwii-campaigns.html |publisher=U.S. Navy |date=20 October 1999 |access-date=13 April 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080409052122/https://www.navy.mil/navydata/cno/n87/history/wwii-campaigns.html |archive-date=9 April 2008 }}</ref><ref>{{cite journal |last1=Zuberi |first1=Matin |title=Atomic bombing of Hiroshima and Nagasaki |journal=Strategic Analysis |date=August 2001 |volume=25 |issue=5 |pages=623–662 |doi=10.1080/09700160108458986|s2cid=154800868 }}</ref>

On 11 July, Allied leaders [[Potsdam Conference|met in Potsdam, Germany]]. They [[Potsdam Agreement|confirmed earlier agreements]] about Germany,<ref name="Williams 2006 90">{{Harvnb|Williams|2006|p=90}}.</ref> and the American, British and Chinese governments reiterated the demand for unconditional surrender of Japan, specifically stating that "[[Potsdam Declaration|the alternative for Japan is prompt and utter destruction]]".<ref name="Miscamble 2007 201">{{Harvnb|Miscamble|2007|p=201}}.</ref> During this conference, the United Kingdom [[1945 United Kingdom general election|held its general election]], and [[Clement Attlee]] replaced Churchill as Prime Minister.<ref name="Miscamble 2007 203_204">{{Harvnb|Miscamble|2007|pp=203–204}}.</ref>

The call for unconditional surrender was rejected by the Japanese government, which believed it would be capable of negotiating for more favourable surrender terms.<ref>Ward Wilson. "The Winning Weapon? Rethinking Nuclear Weapons in Light of Hiroshima". ''International Security'', Vol. 31, No. 4 (Spring 2007), pp. 162–79.</ref> In early August, the United States [[Atomic bombings of Hiroshima and Nagasaki|dropped atomic bombs]] on the Japanese cities of [[Hiroshima]] and [[Nagasaki]]. Between the two bombings, the Soviets, pursuant to the Yalta agreement, [[Soviet–Japanese War|declared war on Japan]], [[Soviet invasion of Manchuria|invaded Japanese-held Manchuria]] and quickly defeated the [[Kwantung Army]], which was the largest Japanese fighting force.<ref>{{Harvnb|Glantz|2005}}.</ref> These two events persuaded previously adamant Imperial Army leaders to accept surrender terms.<ref name="Pape 1993">{{Harvnb|Pape|1993}} " The principal cause of Japan's surrender was the ability of the United States to increase the military vulnerability of Japan's home islands, persuading Japanese leaders that defense of the homeland was highly unlikely to succeed. The key military factor causing this effect was the sea blockade, which crippled Japan's ability to produce and equip the forces necessary to execute its strategy. The most important factor accounting for the timing of surrender was the Soviet attack against Manchuria, largely because it persuaded previously adamant Army leaders that the homeland could not be defended.".</ref> The Red Army also captured the [[Soviet invasion of South Sakhalin|southern part of Sakhalin Island]] and the [[Invasion of the Kuril Islands|Kuril Islands]]. On the night of 9–10 August 1945, Emperor [[Hirohito]] announced his decision to accept the terms demanded by the Allies in the [[Potsdam Declaration]].<ref>Bix, ''Hirohito and the Making of Modern Japan'' pp. 525–526</ref> On 15 August, the Emperor communicated this decision to the Japanese people through a speech broadcast on the radio ([[Hirohito surrender broadcast|''Gyokuon-hōsō'']], literally "broadcast in the Emperor's voice").<ref>Bix ''Hirohito and the Making of Modern Japan'', pp. 526–528</ref> On 15 August 1945, [[Surrender of Japan|Japan surrendered]], with the [[Japanese Instrument of Surrender|surrender documents]] finally signed at [[Tokyo Bay]] on the deck of the American battleship {{USS|Missouri|BB-63|6}} on 2 September 1945, ending the war.<ref name="Beevor 2012 776">{{Harvnb|Beevor|2012|p=776}}.</ref>