Japan’s path from the Sino-Japanese War to the Pacific War had much to do with two major policy decisions. One was the Tripartite Pact which Japan, Germany and Italy concluded, and the other was Japan’s southward advance.
 Who pushed these policies forward and on what sort of judgments and with what intentions were they based? And what went wrong in the decision-making process and how did it happen? Investigation into the start of the Pacific War, which followed the Sino-Japanese War, begins with the Tripartite Pact.

Army moves to find a breakthrough in quagmire of Sino-Japanese War

 Japan concluded its alliance with Germany and Italy on September 27, 1940 (the 15th year of the Showa Era), about two months after the establishment of the second Konoe Cabinet. To understand how the Tripartite Pact came about, it is important to look at preceding events. Japan and Germany, both of which withdrew from the League of Nations in 1933, concluded the Anti-Comintern Pact in November 1936, in preparation for military pressure from the Soviet Union and the Bolshevik drive by the Comintern. Italy joined the pact in 1937. Then in 1938, a scheme to develop the pact into a military alliance began taking shape.

 What was Germany thinking at this point? At the time it was attempting to annex Austria and Czechoslovakia. In order to fend off interference from Britain and the Soviet Union, Germany wanted to hold them in check by using Japan.

 The Army jumped at the German proposal for concluding the pact. The Army, which prioritized the campaign against the Soviet Union, was feeling impatient with the prolonged Sino-Japanese War, which it viewed as a waste of ammunition and military force. The Soviet Union was rapidly building up its military capacity, particularly in the Far East. The Army hoped that Germany wanted to keep Britain and the Soviet Union in check on their European fronts as a way to make up for Japan’s diminishing military capabilities against the Soviet Union; it also hoped both Britain and the Soviet Union would suspend their military assistance to the Nationalist government of China headed by Chiang Kai-shek. But the Navy objected to the Army’s move. It was concerned that if Japan moved ahead with a military alliance with Germany, it would have an adverse impact on relations with Britain and the United States.

 In 1939, officials including Hideo Iwakuro, head of the Army Affairs Section at the War Ministry, and Shigeki Usui, head of the Covert Operation Section of the Army General Staff, gathered almost daily at the official residence of the War Minister, advocating an alliance. However, even when War Minister Seishiro Itagaki vehemently called for the alliance, Navy Minister Mitsumasa Yonai remained strongly opposed to it. Vice Navy Minister Isoroku Yamamoto, who was an aide to Yonai, judged that there was no way for Japan to continue a war against the United States or compete in a naval build-up race. Shigeyoshi Inoue, head of the Naval Affairs Bureau of the Navy Ministry, also warned that “For Hitler, the Japanese are inferior people who lack imagination. But he might see us as people who could be superficially clever and shrewd so that we could be useful as a tool for Germany to use.”

 While the conflict in views between the Navy and War Ministries remained unresolved, the issue of whether Japan should conclude the pact was carried over from the Konoe Cabinet to its January 1939 successor led by Prime Minister Kiichiro Hiranuma.

 At the meeting of five concerned ministers—a de facto inner cabinet session—held on August 8, 1939, Finance Minister Sotaro Ishiwata, following a remark by War Minister Itagaki who said that the consensus of the Army was that the pact should be concluded immediately, questioned Navy Minister Yonai by saying, “We should take into account the possibility of Japan, Germany and Italy fighting a war with Britain, France, the United States and the Soviet Union. Is there any chance of us winning such a war?” Yonai said there was no chance.

 Yet the antagonism between Itagaki and Yonai ended abruptly on August 23, only two weeks after the five ministers meeting, when Germany signed a nonaggression agreement with the Soviet Union, a country which was a potential enemy for both Japan and Germany. Hitler joined hands with Josef Stalin, the Soviet leader, over the division of Poland. At about that same time in 1939, the Japanese Army was defeated by Soviet forces in the Nomonhan Incident at the border of Manchuria and Mongolia.

 In late July, Japan was given notice from Washington that the U.S.-Japan Treaty of Commerce and Navigation had been allowed to lapse. Prime Minister Hiranuma and his Cabinet resigned en masse on August 28, with Hiranuma saying, “The world of Europe is complicated and inscrutable.” With this, the Tripartite Pact was shelved, at least for the time being.

 In September 1939, Germany invaded Poland, which prompted Britain and France to declare war on Germany, thus ushering in World War II. The Cabinet led by Prime Minister Nobuyuki Abe made clear that Japan would not intervene in the war in Europe, forcing the Army, which aimed to find a breakthrough in the war against China with Japan-Germany cooperation, to change its policy.

 According to an Army staff officer’s logbook, “the Army General Staff for its part...has been forced to struggle on with handling contingencies,” while “the War Ministry appears ready to start pulling out the troops now.”

 The Army reportedly had independently formed a policy of withdrawing troops from China, starting in 1941, unless the Sino-Japanese War was resolved within the year.  However, it was not only the commanders in the field who opposed a withdrawal, but some officials including Vice War Minister Korechika Anami were reportedly opposed to it.

 Regardless, it was still a major turning point in the Sino-Japanese War.