The first thing we need to address is: what is the geographical scale of a ‘global’ war? Is it based on where military clashes occur? Or should we take a broader view and consider the geographical extent of state belligerents, some of which may not contribute to direct military operations, as a whole? I subscribe to the latter view - the act of waging war is not limited to the battlefield, but must also extend to the production, transport, logistical and political networks linking the home front to the frontlines. By this logic, Hew Strachan points out that the entry of France, Germany and Britain as belligerents in the First World War automatically elevated the Great War into a global war.^(1) As colonial powers, the mobilisation of and contest over military, economic, agricultural, industrial and manpower resources in overseas colonies meant that the war had reached a global scale.

The global nature of war was equally apparent in 1939, when Britain and French colonies joined their metropoles in the fight against the European Axis powers. Australia, New Zealand, India, South Africa, North Africa, West Africa, Equatorial Africa and Indochina all diverted resources and manpower to the European theatre during the early months of the war, and committed troops to campaigns in North Africa, East Africa, Iraq and Syria. Many of these colonies were not threatened by Axis forces, but their economic and military mobilisation made it clear they were very much part of the general allied war effort.^(2) The movement of resources along shipping lanes meant that the global war had an equally significant naval aspect. Immediately after the declaration of war, German and Italian commerce raiders went after allied shipping in the Atlantic and the Mediterranean, but also in the Indian Ocean, the Pacific and the Arctic. All this, without the direct involvement of the United States, the Soviet Union and the Japanese Empire! The entry of the British and French empires into what was then an European war in 1939 elevated the conflict into a global one.

Now that we've established the nature of global war, time to go back to the actual question: why isn’t the start of the Second Sino-Japanese War on 7th July, 1937, considered the start date of the Second World War? Even by the most charitable definition, the Second Sino-Japanese War was a regional war from 1937 to 1941. As the Japanese Empire was limited to East Asia, economic and military mobilisation remained constrained within the region, while the Republic of China Navy did not have the capability to conduct commerce raiding against Japanese shipping.^(3) Indeed, it was a source of frustration to Chiang Kai-shek and the Guomindang (GMD) government that the Sino-Japanese conflict did not lead to substantial diplomatic, economic and military support from the Soviet Union, Britain and America. At the start of the war, GMD leading figures had hoped that strong resistance to initial Japanese pushes would bolster foreign support of the Chinese cause. Chiang implored all troops on 22 October, 1937 to “make extra efforts...to demonstrate our morale and strength, improve our international status, and win sympathy and support from foreign nations,” in anticipation of the Brussels Conference on 30 October, 1937, convened by the League of Nations to censure Japanese actions and reaffirm China’s right to self-determination. Unfortunately for the Guomindang, participants of the Brussels Conference refused to take concrete action in support of China. The Soviet Union, China's biggest supporter in terms of actual materiel transferred, was unwilling to escalate the situation. On 5 December, 1937, Stalin replied to an enquiry from the Chinese military delegation at Moscow that the USSR would only intervene directly if the majority of the participants of the Brussels Conference agreed to take joint action against Japan.^(4) Chiang continued to encourage his field commanders that the Soviet Union would enter the war to boost morale, but by the end of 1937, it was clear there would be no direct foreign involvement in the Second Sino-Japanese War.

It is true that throughout the 1937-1941 period, the Soviet Union, Britain and the United States did provide economic and military assistance to China. However, American and British economic support was of a start-stop nature - Britain especially could not afford to anger Japan too much, as the mobilisation of the British empire against Germany and Italy left her Asian and Australasian colonies exposed. Widespread sympathy for China in the United States led to heavy sanctions against Japan, but Roosevelt's government baulked at the prospect of direct military conflict.^(5) Perversely, Soviet support for China actually led to Soviet non-participation in the Sino-Japanese conflict until 1945. As John Garver argues, in order to stop or delay a Japanese strike against Soviet Siberian possessions, the USSR was more than happy to support Guomindang China to the fullest extent in her conflict with Japan without actually declaring war on the aggressor.^(6) All three powers supported China to some degree, but also actively avoided the final step of entering the war as a co-belligerent.

The Second Sino-Japanese War only became part of the wider global war in December 1941, when Japan launched surprise attacks against British, Dutch and American colonies and bases in the Pacific. The entry of the allied powers into the Pacific War subsumed the Sino-Japanese conflict into a global war: meetings were held between British, American and Chinese military staff in Chongqing to coordinate the Asian war effort immediately after the attacks, while Chinese forces rushed to assist beleaguered British troops in Burma and Hong Kong.^(7) In the opposite direction, allied resources and manpower flowed into China in a bid to retrain and re-equip Chinese divisions, while the Flying Tigers, a volunteer unit of pilots who resigned from American service to fight against Japan, was incorporated into American military structure as the American 23rd Fighter Group. The governments of Britain, America and China mobilised their nations not for an isolated conflict with the Japanese Empire, but in coordination with each other as part of a global war effort (for better or worse: joint offensives in Burma scheduled for 1942, 1943 and 1944 were delayed for the opening of a Second European Front in France, much to Chinese displeasure). The Second Sino-Japanese War started out as a regional war in 1937, and it was only until 1941 that it became part of the global Second World War.

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^(1) Strachan, Hew. "The First World War as a global war." First World War Studies 1, no. 1 (2010): 3-14.

^(2) Jackson, Ashley. The British Empire and the Second World War. A&C Black, 2006.

^(3) Wu, Di. "The cult of geography: Chinese riverine defence during the Battle of Wuhan, 1937-1938." War in History (2020).

^(4) Yang, Tian-shi. "Chiang Kai-shek and the Battles of Shanghai and Nanjing." In The Battle for China: Essays on the Military History of the Sino-Japanese War of 1937-1945, edited by Mark Peattie, Edward J. Drea, and Hans J. Van de Ven, pp. 143-158. Stanford: Stanford University Press, 2011.

^(5) Iriye, Akira. The origins of the Second World War in Asia and the Pacific. Routledge, 2014.

^(6) Garver, John W. "China's Wartime Diplomacy." In China's bitter victory: The war with Japan, 1937-1945, edited by James C., and Steven I. Levine, pp. 22-45. ME Sharpe, 1992.

^(7) Ch'i, Hsi-sheng. The Much Troubled Alliance: US–China Military Cooperation During the Pacific War, 1941–1945. 2016.