The P-70 Ametist was an anti-shipping missile carried by Soviet and Indian Charlie-I submarines, as well as the Soviet Papa class submarine. It was soon succeeded by the P-120 Malakhit.
In 1960s the Soviets started work on a new missile that could be fired whilst submerged, and a submarine to carry it. These became the P-120 Malakhit and Charlie class submarine.
However, problems with the engines of the P-120 Malakhit forced the Soviets to design a sub-launched missile based on the P-15M Termit as a stopgap measure for the first batch of Charlie submarines. This became the P-20L, later renamed the P-70 Ametist.
