Complex sentence: The new medium tank, Type 97 Chi-Ha, was introduced in 1937 and an improved version (Type 97 Shinhoto Chi-Ha) remained in production until 1943.
Split into simpler sentences: The new medium tank, Type 97 Chi-Ha, was introduced in 1937. Later, an improved version known as the (Type 97 Shinhoto Chi-Ha) remained in production until 1943.