
For this to work the German tanks were all equipped with radios, which provided unmatched command and control for flexible employment. German doctrine stressed the use of rapid movement, mission-type tactics and combined-arms where tanks operated with mobile infantry and air support this doctrine was popularly called Blitzkrieg. Germany concentrated the tanks and the few infantry transport vehicles it had into Panzer division. However, in their tactical employment the German tanks dominated all rivals early in the war. The early tanks of Germany were inferior to many of their opponents' tanks in the areas of armor and firepower. The United Kingdom, the US, the Soviet Union, and France produced significant numbers of tanks before and during World War II. In particular, the gun-vs-armor race of the war led to rapid improvements in firepower and armor (both in thickness and design). The war accelerated the pace of change in design. By the beginning of the war in September 1939, tanks were available that could travel hundreds of miles on their tracks with a limited number of breakdowns. Reflecting the growth of the automotive industry, tank engines, transmissions, and track systems were improved. Tank design gradually improved in the inter-war period also. In addition to infantry support, tanks fulfilled traditional cavalry roles, provided mobile artillery support, and were adapted to combat engineering roles. Initially, tanks had been used for close support of infantry, but as modern mechanized doctrine was developed by several armies, tanks became an essential part of the combined-arms team. The doctrine of armored warfare changed radically in the inter-war years as armies sought ways to avoid the deadlock imposed by modern firepower and looked for the means to restore offensive power on the battlefield. Walter Christie which allowed considerably longer movement of the suspension than conventional leaf-spring systems then in common use, and allowed the tanks to have considerably greater cross-country speed. A breakthrough in tank design was the Christie suspension: a suspension system developed by American engineer J. World War I tanks moved at a walking pace, were relatively unreliable, and the best usage of them was still developing up to the war's end. Tanks of the First World War reflected the novelty of the idea and the primitive state of the automotive industry. The tank was invented by the British in 1916 and first used during World War I, with nearly simultaneous development in France.

T3E2 tank with Christie suspension crossing an obstacle during tests in 1936
