The Tosei Ha, Japanese for Control Group faction, was a faction of the Imperial Japanese Army which formed in the aftermath of the invasion of Manchuria. Like its rival faction, the Kodo Ha, it supported further expansion of the Japanese Empire. However, the Tosei Ha was more cautious in its approach, seeking to adhere to strict guidelines and seek more formal rules of engagement, achieving its aims while working within the political system. They resisted to Kodo Ha's calls to expand further into China to gain a more advantageous position against the the Soviet Union.
In February 1936, the Japanese First Infantry Division revolted in Tokyo in support of the Kodo Ha, killing many government ministers and civil servants. The mutiny was eventually put down by imperial order. The Tosei Ha, at least ostensibly, maintained control of the army. However, Woo felt that the Tosei Ha's victory over the Kodo Ha was not total, as did some members of the Tosei Ha itself, reflected by their subsequent change of policy. In July 1937, Koda Ha commanders in Manchuria provoked a fight between a handful of Chinese soldiers at Marco Polo Bridge. With Japanese troops in action against the Chinese, the Tosei Ha was forced to move the government onto a war footing, beginning the Pacific War. (PROSE: The Shadow of Weng-Chiang)