The Chieftain is the second generation main battle tank after World War II developed in the UK.
Development began in the 1950s with the aim of integrating the main battle tank, Centurion, and its supporting heavy tank Conqueror, and production-type mass production began in May 1963. The British Army were skeptical of the concept of "enhancing mobility at the expense of armor defense" in the 1950s, so the chieftain adopted heavy armor and used a new L11 120mm gun for protection of occupants. It is equipped with a powerful tank gun, which is capable of defeating Soviet MBTs such as T-55 and T-62 medium tanks at distances of up to 4,000 m, and the Soviet Union is equipped with a 125 mm smooth bore gun to counter this. It is said that the T-64 and T-72 tank series have been developed.
Chieftain Mk.10 is a Mk.7 modified Mk.9 equivalent and combined armored front half of the main gun.Mk.11 modified Mk.8 to Mk.10 equivalent and improved NBC protection. And the searchlight on the port side of the turret was changed to TOGS.