Tsuji helped plan the Sook Ching, a systematic massacre of thousands of Malayan Chinese who might be hostile to Japan. He was then transferred to the staff of General Homma in the Philippines. After the US surrendered there, Tsuji sought to have all American prisoners killed and encouraged the brutal mistreatment and casual murder of prisoners in the Bataan Death March. He also had many captured officials of the Philippines government executed, including by ordering the execution of Filipino Chief Justice José Abad Santos and the attempted execution of former Speaker of the House of Representatives Manuel Roxas. After the war, the Japanese war criminals were prosecuted, but Tsuji fled and avoided the Sook Ching trial. Some other army officials, who had followed Tsuji's command, were charged, and two of them were executed. Because of the war crimes at the Bataan Death March, General Homma, who considered himself a humanist and was surprised to hear the facts of death march after the war, was held responsible for his subordinates and was executed while Tsuji was on the run. World War II In 1932, Tsuji saw action in China, and subsequently travelled as far as Sinkiang. He served as a staff officer in the Kwantung Army in 1937–1939. His aggressive and insubordinate attitude exacerbated the Soviet–Japanese border conflicts, and helped incite the Battle of Khalkhin Gol in 1939. After the defeat at Khalkhin Gol, Tsuji opposed any further conflicts with the Soviet Union. After their attack on the Soviet Union in 1941, the Germans urged the Japanese to join the invasion, and many in the Japanese military wanted to avenge the defeat at Khalkhin Gol. However, Tsuji was an influential advocate of the attack on the United States. General Ryukichi Tanaka testified after the war that "the most determined single protagonist in favor of war with the United States was Tsuji Masanobu." Tsuji later wrote that his experience of Soviet firepower at Khalkhin Gol convinced him not to attack the Soviet Union in 1941. His protectors in the Army got him safely transferred to Taiwan, where he helped organize the Army's jungle warfare school. He was then assigned to the Operations Section of the General Staff, where he became a strong advocate of war with the United States and Britain. It has been alleged that in late 1941, he planned the assassination of Prime Minister Konoye if Konoye achieved peace with