The Chi-Nu retained the same chassis and suspension of the Type 1 Chi-He, but with a new large hexagonal gun turret and a commander's cupola. The Type 3 75 mm tank gun was one of the largest guns used on Japanese tanks. The thickest armor used was 50 mm on the front hull; it also had 25 mm on the turret, 25 mm on the sides and 20 mm on the rear deck.
The Chi-Nu's design incorporated a new large hexagonal gun turret and commander's cupola, while retaining its chassis and suspension from the Type 1 Chi-He. The Type 3 75 mm tank gun was one of the largest guns used in Japanese tanks, with the thickest armor being 50 mm on the front hull, 25 mm on the turret, sides, and 20 mm on the rear deck.