From Japan's point of view, the divided, weak, impoverished, and backward East Asian continent is the basis for Japan to maintain its hegemony in the Asia-Pacific region, and once the East Asian continent pursues reunification, it will inevitably take back the stolen sovereignty, resource dominance, and market possession rights from Japan...... Therefore, a collision between China and Japan is inevitable

。 At that time, the international situation had changed dramatically, and in the summer of 1940, Germany succeeded in blitzing Western Europe, the Netherlands and France were defeated one after another, and Britain was also in danger. On April 15, 1940, Foreign Minister Arita issued a statement declaring that Japan was inextricably linked with the countries of Southeast Asia and the South Seas region, and that Japan "cannot ignore any changes in this region." On June 29, he delivered a speech on the so-called "Building a New Order in Greater East Asia." On July 26, the Second Konoe Cabinet threw out the "Outline of Basic National Policy" and formulated the "Outline for Handling the Current Situation to Adapt to the Evolution of the World Situation", declaring that the fundamental policy of Japan ** is to "believe" that in the war in Europe, the old forces are succumbing to the power of the emerging powers, and only Britain is left to survive, and the world situation is changing quite dramatically. The opportunity to establish self-sufficiency in the South Seas east of India and north of Australia and New Zealand will never be the same as today." On August 1, Foreign Minister Yoyoshi Matsuoka officially put forward the slogan of establishing a "Greater East Asia Co-Prosperity Sphere" in his first speech after taking office. The intention of this move is, firstly, to provide a huge and reliable market and a stable source of raw materials for Japan's manufacturing industry economically; Second, militarily, the Blocking Alliance proposed to turn Southeast Asia and the western Pacific region into Japanese colonies, and then establish a "self-sufficient" economic system. At this point, Japan's "southward expansion" policy was finally established, [ In mid-December 1940, a military research department was established in Taiwan Province of China, which was responsible for "the investigation of military intelligence and the geography of military information in various parts of the south", and in the same month, the South China Front was ordered to carry out tropical and landing combat training for its subordinate units. In March ~ April of the following year, the Japanese base camp conducted a joint exercise of actual forces of land, sea and air forces after the hypothetical occupation of Malaya and continued to capture Singapore, and conducted long-distance sea flights (including night flights) and communication and liaison training for the air force, and created an airborne unit in September 1941.

Japan is extremely poor in resources, and most of its main strategic resources rely on imports, while Southeast Asia is rich in resources, especially "the Dutch East Indies is the oil treasure house of East Asia, with an annual production of about 8 million tons, which is 20 times that of Japan." At that time, Japan needed about 5 million tons of oil a year, and its self-sufficiency capacity was less than one-tenth." The geographical location of Southeast Asia is very important, and the occupation of Southeast Asia can not only cut off the two important road communication lines of the United States and Britain to aid China: the Yunnan-Vietnam Railway and the Yunnan-Burma Highway, but also go west into the Indian Ocean to threaten India and join forces with the German army in the Middle East, and to the south can capture Australia and dominate the Western Pacific.

Contradictions between Japan and the United States have intensified

Germany's success in blitzkrieg in Western Europe caused European and American imperialism to devote its main energies to the European theater and had no time to look eastward, creating a "vacuum" in the skies over Southeast Asia and giving Japanese imperialism an opportunity to take advantage of. Japan changed its previous wait-and-see hesitation to sign a trilateral military alliance between Germany, Italy and Japan, and on September 27, 1939, the "German-Italian-Japanese Triple Alliance Treaty" was signed in Berlin. It has realized the basic policy of Japanese imperialism of "adapting to the sudden changes in the world situation, rapidly building a new order in East Asia, and seeking to strengthen the axis of Japan, Germany, and Italy."

The contradictions between the United States and Britain and Japan in the Far East have a long history, and in particular, Japan's launching of a full-scale war of aggression against China has seriously damaged the economic interests of the United States and Britain in China. However, due to the increasingly tense situation in Europe, the decline of Britain's comprehensive national strength, and the powerful isolationist forces in the United States, they tried their best to avoid conflict with Japan in the Far East in a vain attempt to "obtain Japan's concessions at the expense of China's interests and achieve a conditional compromise between the two sides, so as to preserve the basic interests of Western countries in China." Under the guidance of this ideology, the United States and Britain adopted a policy of appeasement of compromise and concession toward Japan. In handling the issue of relations with Japan, Britain has tried to push the United States to the front line to deal with the crisis. As a sign of sincerity, Britain also signed the "Aritta-Claeon Agreement" with Japan, which "recognized Japan's special status in China and the responsibility of the Japanese army to maintain law and order in the occupied areas."

In the face of Japan's ever-expanding aggression, the United States' trade with Japan, especially the export of strategic raw materials to Japan, continued to increase. After 1932, the United States supplied 90 percent of Japan's imports of scrap steel, 65 percent of petroleum and petroleum products, 90 percent of copper and 45 percent of lead, and 70 percent of the machine tools necessary to expand the military industry. In 1937, the United States exported a total of $288,558,000 of materials to Japan, of which war materials accounted for 58%; In 1938, a total of 239.575 million US dollars of materials were exported to Japan, of which war materials accounted for 67%; In 1939, 90% of Japan's oil imports came from the United States.

The appeasement policy pursued by the United States and Britain fueled Japan's ambitions and accelerated the pace of Japan's launching of the Pacific War. After the outbreak of the war in Europe, Japan took advantage of the defeat of France and the British siege of the British Isles, and forced them to close the Yunnan-Vietnam Railway and the Yunnan-Burma Highway, and forcibly stationed themselves in northern Indochina in September, taking the first step in seizing European and American colonies in Southeast Asia by force. In July 1941, it forcibly stationed itself in southern Indochina and forced France to sign the "Japan-France Protocol on the Mutual Defense of Indochina", thus controlling the naval bases of Saigon and Cam Ranh Bay, and turning Indochina into a strategic base and logistics base for the realization of its "southward expansion" plan.

After the outbreak of war in Europe, the United States and Britain held that Britain itself was a European country with a huge colonial empire, and if Japan's expansion in East Asia threatened Britain's limbs, then Germany's expansion war in Europe threatened its heart, and it was obvious that Germany's threat was greater than Japan's threat to it. Europe is an important trading partner of the United States and the focus of its struggle for hegemony, and a large part of the United States' overseas investment is in the British Empire and European countries, and "at least 42 percent of the $12 billion in foreign investment of the United States is in the British Empire." Therefore, the United States and Britain put the defeat of Hitler in the European theater in the first place. On January 29 ~ March 27, 1941, the chiefs of general staff of the United States and Britain reached the ABC-1 agreement at secret talks in Washington, which for the first time clarified the strategy of "Europe first and then Asia". Under the guidance of this strategy, the main task of the Allies was to concentrate superior forces to defeat Germany, while only to take defense against the Japanese offensive to be launched in Southeast Asia.

In April ~ May 1941, the U.S. Pacific Fleet, which was supposed to defend Southeast Asia, had 3 battleships, 1 aircraft carrier, and 5 destroyers ordered to be transferred to the Atlantic Fleet to deal with the British crisis situation, which greatly weakened the defense force in Southeast Asia.

In January ~ March 1941, the Washington Conference of the Chiefs of General Staff of the United States and Britain formulated a global strategy of "Europe first and Asia later", but on the issue of Far East defense, the United States and Britain still had big differences, that is, they did not reach an agreement on "who should play the main role in resisting Japan in the Pacific". In April 1941, British Far East Commander Popam convened two meetings in Singapore attended by representatives of the Netherlands, Australia, New Zealand, the United States and other countries, and formulated an agreement known as "ADB", and the strategic deployment "required to concentrate on Singapore as the main base, and at the same time hold the two forward bases of ** and the Philippines, and blockade and attack Japan from these two places". However, the United States refused to accept its strategic scope and its obligations too many, and the plans of the United States and Britain to take joint action on the defense of the Far East were once again bankrupt.

Before the outbreak of the Pacific War, China and Britain had realized the importance of Burma's strategic location and the possibility of being attacked by Japan, and began to plan a common defense plan, and signed the "Sino-British Agreement on the Mutual Defense of the Yunnan-Burma Road" on December 23, 1941, but Britain refused to allow Chinese troops to enter Burma on the grounds that "a formal alliance is sufficient to ensure the security of Burma" in the early stage of the Pacific War, and it was not until February 1942 that Britain realized that it could not guarantee the security of Burma by its own strength. Ask the Chinese army to fight in Burma.

In the face of Japan's imminent aggression, the United States and Britain have adopted corresponding economic sanctions against Japan. On July 26, 1940, the United States announced the imposition of a "moral embargo", "export license", "economic embargo" and other measures against Japan, and after Japan entered Indochina, it imposed a scrap steel export license system on Japan, and Britain also reopened the Yunnan-Burma Highway on October 18 and began to transport supplies to China. On July 28, 1941, the United States and Britain froze Japanese capital in the United States and Britain, which was "the first time since Japan began its aggression and expansion in 1931 that the two countries took measures to resist Japan's aggression, and it was the first coordinated action between the two countries." However, from these sanctions, the United States and Britain are still reluctant to provoke Japan too much, especially the absence of an embargo on oil. On July 26, 1940 ~ January 15, 1941, the United States signed a 7 million barrel oil export license with Japan, of which 3 million barrels of oil have been imported into Japan, accounting for 1/3 of the average export rate in 1936~1939. Until August 1, 1941,

The United States announced an oil embargo on Japan, and in September the United States and Britain stopped all trade with Japan.

From March ~ December 7, 1941, the United States and Japan held a nine-month "marathon" negotiation, which bought time for Japan to start a war. During this period, Japan completed the deployment of combat forces in the south; In 1941, Japan produced 6 million tons of pig iron, 5.5 million tons of steel, more than 5,000 aircraft, and 48 ships (including 5 aircraft carriers, 1 battleship, and 1 cruiser), completing the final preparations for war.