A large number of political and military leaders in Japan made weighty and critical decisions with regard to the Manchurian Incident, the Sino-Japanese War of 1937–45, the Pacific War, which ended with Japan’s defeat and marked the end of World War II. Who made—or had no choice but to make—these decisions? For what reasons? Were there no other options? The Yomiuri Shimbun’s “WAR RESPONSIBILITY—delving into the past” series begins with the Manchurian Incident.

Japan under three kinds of foreign pressure

 The Manchurian Incident happened in 1931 (the sixth year of the Showa Era). It escalated to the Sino-Japanese War and finally led to the Pacific War. When we trace the origins of World War II, we come across the Manchurian Incident, undertaken by the Imperial Japanese Army with the aim of occupying Manchuria—a move in conflict with the then prevailing international order.

 Japan gained an opportunity to establish a stronghold in Manchuria—now known as northeast China—following its victory in the 1904–05 Russo-Japanese War. As a result of that war, Japan acquired the Russian leasehold on Kwantung (Guandong) in the southern part of the Liaodong Peninsula and the Russian rights to the South Manchurian Railway Company that ran between Changchun and Port Arthur (Lushun). To protect these new interests, Japan dispatched troops to southern Manchuria. From the very beginning of the troop deployment, the Imperial Japanese Army cherished an ambition—to control the whole of Manchuria.

 Before looking further into developments in Manchuria, it is useful to turn the clock back to the Meiji Era (1868–1912). In 1906 (the 39th year of Meiji), an official government council meeting was held to discuss Manchuria-related issues. During the session, Gentaro Kodama, Chief of the Army General Staff, proposed that “one person be entrusted with sovereign power in Manchuria” and, “to that end, a new government should be established there to completely take the helm.” The chair of the council, former Prime Minister Hirobumi Ito—one of the genro senior statesmen who exercised collective leadership—opposed Kodama’s opinion, saying, “Manchuria is by no means our territory. Purely and simply, Manchuria is the territory of China under the Ching [Qing] Dynasty.”

 However, the implication of Kodama’s remarks was too clear to be forgotten. The Army continued to cherish a desire to rule Manchuria, becoming more and more ambitious as the years went by—until it finally took action in the Showa Era (1926–89).

 Why did the Imperial Japanese Army want to occupy Manchuria?  According to a historian specializing in the Showa Era: “The military had a sense of unity with Manchuria [a belief that led to the Japan-Manchuria alliance]...because of the fact that the Japanese Army won the Russo-Japanese War—the basis for its development—thanks to its officers and men who shed blood in the land of Manchuria.”

 The desire to advance to Manchuria, which was referred to as “the Manmo (Manchuria-Inner Mongolia) Issue,” consistently remained “the supreme basic policy of the Army.”

 What was the international situation surrounding Japan at this time?

 During World War I (1914–18), Japan issued its “Twenty-One Demands” on China in 1915 in an effort to expand its rights there. The ultimatum, seen by the Chinese as a “national humiliation,” aroused Chinese nationalist sentiment and gave momentum to the campaigns for regaining China’s sovereign rights and fighting against Japan.

 Determined to realize China’s national unification, Kuomintang leader Chiang Kai-shek, the successor to Sun Yat-sen (Sun Yixian) who led the 1911 revolution that ended the rule of the Qing Dynasty, launched the Northern Expedition in 1926. His offensive put pressure on the Manchuria-Inner Mongolian region.

 For Japan, the success of the Russian Revolution of 1917 could not be overlooked. With a strong belief in the necessity of securing natural resources such as iron ore and coal in Manchuria in preparation for an all-out war, the Army thought that it would have to bring Manchuria under its control as early as possible to confront the Soviet Union, which then became a potential enemy of Japan. In addition, communist ideology began to have an impact on Japan’s politics and society.

 Following the end of World War I, the League of Nations came into being in 1919 with U.S. President Woodrow Wilson as its driving force. As for East Asia, a new international order was sought under the so-called Washington Treaty system. The Nine-Power Treaty, in particular, required countries, including Japan, who were signatories to the pact, to respect the sovereignty, independence and territorial integrity of China.

 As a result, according to political scientist Junnosuke Masumi: “Japan was faced with three kinds of foreign pressure.”

 The three-way pressure was comprised of the increased pressure on Japan under the Washington Treaty system by Western imperialist powers such as Britain and the United States, the pressure of the sudden rise of nationalism in China and that of the Soviet Union and communism.

 In 1923 (the 12th year of the Taisho Era), Japan began to view the United States as a potential enemy under its revised Imperial Defense Policy, and the U.S. Congress passed the Immigration Act of 1924 restricting further Japanese immigration to the United States.

 Farming communities in Japan were impoverished due to the Showa Depression of 1930–32, with disputes taking place between tenant-­farmers and landlords and between employees and company owners. Although anti-communist, nationalist campaigns calling for “national reform” emerged, Marxism spread. Against this background, Manchuria was recognized as Japan’s “bastion” of national defense and economic development.

 In those days, various local warlords maintained individual strongholds in China. In order to maintain its interests in Manchuria and Inner Mongolia, Japan supported Chang Tso-lin (Zhang Zuolin), a warlord in northern China. The Cabinet of Prime Minister Giichi Tanaka sent troops to Shandong, China, in two waves between 1927 and 1928 to block Chiang Kai-shek’s Northern Expedition and protect Japanese residents there.

 After the first expedition of Japanese troops to Shandong, the government held the Toho Kaigi (the Conference on the East)—in Tokyo in 1927 to discuss Japan’s policy vis- vis China. Among the participants were Shigeru Yoshida, Consul General in Mukden (Hoten in Japanese, presently Shenyang); Eitaro Hata, Vice War Minister; Jiro Minami, Vice Chief of the Army General Staff, Nobuyuki Abe, chief of the Military Affairs Bureau of the War Ministry; Nobuyoshi Muto, Commander of the Kwantung Army; Iwane Matsui, chief of the Second Section of the Army General Staff of the Imperial Japanese Army; and Kichisaburo Nomura, Vice Chief of the Naval General Staff. Tsutomu Mori, Parliamentary Vice Foreign Minister, played a leading role in the conference. In closing, he summarized the meeting as follows:

 “Sovereignty over Manchuria rests with China as pointed out by Minister [Kijuro] Shidehara [who as Foreign Minister showed a conciliatory stance toward Britain and the United States]. Nevertheless, it doesn’t belong to China alone. Japan has the right to take part... Japan will protect Manchuria as it is our first line of defense.”

 During the conference, Mori showed his intention to have Japan confront the League of Nations, the Treaty for the Renunciation of War as an Instrument of National Policy—better known as the Kellogg-Briand Pact— and the Nine-Power Treaty.

 Acting in concert with this 1927 conference on Japan’s China policy, the Kwantung Army stationed in Manchuria prepared a document spelling out its vision for Manchuria and Inner Mongolia. It specifically called for the establishment of a pro-Japanese regime that would govern the three provinces in eastern Manchuria—Liaoning, Jilin and Heilongjiang—and the Rehe area. “Warlord Chang Tso-lin could be appointed as the head [of the regime]. In the case of refusal, [Japan] should establish an exclusive hold over Manchuria and Inner Mongolia even if it means resorting to military action.”

 Chang Tso-lin was assassinated on June 4, 1928, when his train returning to Shenyang was bombed. Two months before the incident, Colonel Daisaku Komoto, a senior officer of the Kwantung Army, wrote a letter to Rensuke Isogai, one of his juniors at the Osaka Army Cadet School, saying, “If Chang Tso-lin and those like him die by the roadside, that won’t be a problem. It will be carried out this time by any means.” Chang’s assassination turned out to be the harbinger of the Manchurian Incident.

 Following the assassination of Chang Tso-lin, his son, Chang Hsueh-liang (Zhang Zueliang), made known his participation in the Kuomintang regime which was opposing Japan. Reacting strongly to Chang Hsueh-liang’s move, the Manchurian Youth League, set up by Japanese residents in Manchuria, demanded that Manchuria become an independent state. Moves by Japanese residents thereafter prompted Japanese military action on various occasions.

 Another supposed consequence of the 1927 conference in Tokyo on Japan’s policy toward China was a document called “Tanaka’s Material for the Throne.” As reported by Chinese newspapers, the document gave rise to anti-Japanese sentiment in China. During the International Military Tribunal for the Far East, the document was produced as evidence of Prime Minister Giichi Tanaka’s report to Emperor Showa about his aggressive policy toward Manchuria and Inner Mongolia. However, the document in question turned out to be false.