After his promotion to major general in July 1938, Tsuchihashi became chief of staff of the IJA 21st Army in August 1939, which was transferred to combat operations in the Second Sino-Japanese War as part of the China Expeditionary Army. The primary role of the IJA 21st Army was the Canton Operation, together with the Imperial Japanese Navy’s 5th Fleet, which it completed by the end of the year. The IJA 21st Army was disbanded on February 9, 1940, and Tshuchihashi returned to Tokyo to become military liaison to the Chinese Embassy. After his promotion to lieutenant general in August 1941, he was sent to Taiwan in September 1941 to command the newly-formed IJA 48th Division. After the outbreak of the Pacific War, the IJA 48th Division was among the first Japanese forces to land in the Philippines as part of the IJA 14th Army, and Tsuchihashi's forces captured Manila, but did not participate in the Battle of Bataan. Instead, in January 1942 his division was transferred to the control of the IJA 16th Army in eastern Java, where was assigned the capture of Surabaya and its strategic oil fields on 7 March 1942. Afterwards, Tsuchihashi and the IJA 48th Division was subsequently assigned to garrison the island of Timor. Although the island had been captured by Japan in the Battle of Timor, much of the island was still in the hands of Australian and Dutch commandos. Tsuchihashi launched a major counter-offensive in an attempt to push the Australians into a corner on the south coast of the island. The Japanese also recruited significant numbers of Timorese civilians, who provided intelligence on Allied movements.. The island was secured when the remaining Australian commandos were evacuated in December 1942. In November 1944, Tsuchihashi was sent to French Indochina to reorganize and take command of the 38th Army. In March 1945, he played a crucial role in the Japanese coup d'état in French Indochina and became the provisional Governors-General of French Indochina. Tsuchihachi maintained the Japanese policy of neutrality in Indochinese internal politics, and formed a government of French-trained but nationalist ministers.Just before the Japanese surrender, Tsuchihashi met with envoys of the Viet Minh and agreed to turn over power to their movement; however, only days later, French forces arrived to reimpose colonial rule. After the surrender of Japan, Tsuchihashi was taken prisoner by the Nationalist Chinese in Hanoi and held in a prisoner of war camp in Guangdong province, China. In January 1948, he was transferred to French control in Saigon, where he remained until he was released in July 1949. He returned to Japan in June 1950, where he lived in obscurity until his death in 1972.
