Facing a rising tide of Chinese nationalism and anti-Japanese sentiment in Manchuria, a handful of activist Guandong Army staff officers undertook unauthorized initiatives, such as the assassination in June 1928 of Manchurian warlord Zhang Zuolin (Chang Tso-lin). On 18 September 1931, Lieutenant Colonel Ishihara Kanji and Colonel Itagaki Seishiro arranged to blow up a section of Japanese railway track outside Mukden (now Shenyang), Liaoning Province, which they then falsely blamed on the Chinese. The Mukden Incident was the excuse for the Guandong Army to initiate fighting with local Chinese forces. In this, the so-called Manchurian Incident, the Guandong Army (without the approval of the Tokyo government) embarked on the conquest of most of the rest of Manchuria, leading to the establishment on 1 March 1932 of Manzhouguo (Manchukuo). In 1934, the Japanese installed as ruler Aixinjueluo Puyi (Aisingioro P'u-i, known to Westerners as Henry Puyi), the last emperor of China's Qing (Ch'ing) dynasty. The new state was then known as Manzhoudiguo (Manchoutikuo, the Manzhu [Manchu] Empire). It was in fact a puppet Japanese state.
The leaders of the Guandong Army regarded the Soviet Union as Japan's chief enemy. Throughout the 1930s, the two sides increased their forces in the border area of Korea, Manchuria, and the Soviet Far East, and border clashes between Japanese and Soviet troops increased. These confrontations included some heavy fighting in the Chagkufeng Incident (July-August 1938) and the Nomonhan Incident (May-September 1939).
Following the German invasion of the Soviet Union in June 1941, the Guandong Army expected a German victory. It conducted a mobilization exercise to prepare for an attack on the Soviet Union between August and October as soon as the Soviets had transferred forces from Manchuria to the European Front. Twelve Japanese divisions in Manchuria, two in Korea, and two from Japan participated in this exercise. Much to the disappointment of Guandong Army leaders, Tokyo decided instead to move into resource-rich south Asia. Supreme Headquarters in Tokyo enjoined Guandong Army leaders to avoid all border conflicts. Following Japan's string of early victories in Southeast Asia and the Pacific, and again anticipating a German victory, Japan withdrew forces from the Pacific Theater to reinforce the Guandong Army for war against the Soviet Union.
However, in conjunction with U.S. advances in the Pacific from February to July 1944, Supreme Headquarters withdrew 10 army divisions and 2 air divisions from Manchuria to the Pacific. The Guandong Army became a hollow force and easily fell prey to Soviet forces, which invaded Manchuria at the end of the war. Within two weeks of the Soviet strike into Manchuria, commander of the Guandong Army General Yamada Otozo surrendered, and the Guandong Army was disarmed. Some 60,000 men of the Guandong Army were killed in the fighting. After the cease-fire, another 185,000 died in Manchuria. About 600,000—including Japanese troops from North Korea, Sakhalin, and the Kuril Islands—were detained in prisoner-of-war camps, where they were forced to work through 1950. The last group of prisoners was not released until 1956. In those labor camps, more than 55,000 died of illness or malnutrition. Asakawa Michio
Harries, Meirion, and Susie Harries. Soldiers of the Sun: The Rise and Fall of the Imperial Japanese Army. New York: Random House, 1991.; Takashi Nakayama. Kanto Gun [Guandong Army]. Tokyo: Kodan Sha, 2000.