The Chi-Ha Kaiwas the most capable Japanese tank that saw combat in WWII. Being an upgrade on the Chi-Ha, it was armed with a new turret (ShinHōtō) boasting the Type 1 (47 mm) cannon to compete with late 1930s armour. Proving themselves very successful in the early Pacific campaign through Corregidor Island and Malaya, effectiveness fell flat when faced against the M4 Shermans of the 1940s, and as a result created the negative stigma of Japanese tank quality.
The Chi-Ha Kai was introduced along with the initial Japanese Ground Forces tree in Update 1.65 "Way of the Samurai". It serves as the true introduction to Japanese combat tanks being equipped with higher velocity cannons and relatively dangerous post-penetration damage. Being built on the Chi-Ha, the only main difference is the turret, mobility will remain the same but comes with a more capable cannon and an additional crew member.