To limit costs , it had to be built like a self - propelled gun , with the main weapon in the hull .
In January 1921 a commission headed by General Edmond Buat initiated a project for such a vehicle .
To limit costs , it had to be built like a self - propelled gun , with the main weapon in the hull .
In January 1921 a commission headed by General Edmond Buat initiated a project for such a vehicle .