The Type 97 medium tank Chi-Ha, the most widely produced Japanese medium tank during World War II, featured armor around 25 mm thick on the turret sides and 30 mm on the gun shield. Mitsubishi produced around 3,000 units, including specialized versions. Initially, it was equipped with a Type 97 57 mm gun to support infantry, but its limitations were exposed during the 1939 Battles of Khalkhin Gol against the Soviet Union, leading to the development of a more effective 47 mm gun by 1941. This new high-velocity gun was mounted on the Type 97 Shinhōtō Chi-Ha or Type 97-Kai ("improved") version, which featured a larger turret accommodating three crew members and started replacing the older models in 1942. The Shinhōtō Chi-Ha saw first combat in the Philippines in 1942 at Corregidor Island. Despite vulnerabilities to Allied tanks like the US M3 Lee, British M3 Grant, M4 Medium, and Soviet T-34, the improved firepower of the 47 mm gun made it the most effective Japanese tank in the Pacific War.