After World War II, the Czechoslovakians decided to develop their own heavy SPG. The main task was to combine the component solutions and motor-transmission unit of Soviet self-propelled guns with a German chassis, which would ensure smoother movement and better load distribution. A secondary issue was increasing the rate of fire, and reducing the temperature conditions of firing was seen as the solution. The designers developed a liquid cooling system for the gun; however, this turned out to be very cumbersome and included a huge supply tank and pump unit that required the power supply to be changed and a more powerful generator to be installed. Because of these problems, as well as the difficulty of fitting Soviet transmission to a German chassis, the project was terminated.