The following year, Type 89 CHI-ROs were included as an armored force was formed for the first time as part of the regular Japanese Army. Three regiments of CHI-ROs were formed, each consisting of two companies with ten tanks each. Their task was to provide close support to the infantry. They proved of such value, especially in Manchuria, that three more regiments were formed in 1934. In that same year, a new air-cooled diesel engine was installed in new production Type 89s. The Army had determined that the air-cooled diesel was a more efficient engine for tanks, especially in arid northern China and Manchuria. A diesel engine was preferred because more diesel fuel than gasoline could be produced per barrel of oil. All Type 89s equipped with the diesel engine were referred to as Type 89Bs.
Over the next few years, other changes were made, none considered major. A new type of cupola was installed; a new mantlet for the gun was devised that gave more protection; and an armored sleeve was placed around each machine gun. New frontal armor plate with a shallow slope provided more protection for the driver.
Type 89s were used widely throughout China after 1937, when the war began in earnest. They were also used against Soviet forces in the Soviet-Japanese War of 1939 when the Japanese Kwangtung Army crossed the Mongolian border near No-men-k'an in May 1939, By 1942 the Type 89 was being replaced, but many CHI-ROs saw action in the Philippines, Malaya, and Burma, They were also often used in essentially static defense positions on Japanese-occupied islands.
The Type 89 was an excellent tank for use against an enemy without heavy antitank guns or better armored and gunned tanks. They served their purpose in supporting the tide of Japanese conquest in China from 1937 and in southeast Asia between 1940 and 1945.
Learn more about the Type-89 CHI-RO Medium Tank's specifications on the next page.