Heavy tank
The Char 2C was one of the largest tanks ever produced. At the start of World War II, France and the Soviet Union were the only countries to have inventories of heavy tanks, such as the Char B1, T-35, and KV-1. The Matilda II was designed under the British infantry tank concept which is similar to the heavy tank having thick armor and weighing more than their other tanks. It’s usually separate because they have less firepower with their cruiser tanks (comparable to mediums) at the time having the same main armament but more machine guns. Later war examples were the German Tiger I and II, as well as the Soviet IS series. Note that "heavy" versus "medium" is more a question of tactical roles than weight; the Panther, for example, was a "medium" tank that outweighed most Allied "heavy" tanks.
Tanks in the German Army
After the war, many nations needed to have tanks, but only a few had the industrial resources to design and build them. During and after World War I, Britain and France were the intellectual leaders in tank design, with other countries generally following and adopting their designs. Germany was one of the countries which began to design and build their own tanks. The Treaty of Versailles had severely limited Germany's industrial output.
Among the German proponents of mechanization, Gen. Heinz Guderian was probably the most influential. Guderian's 1914 service with radiotelegraphs in support of cavalry units led him to insist on a radio in every armored vehicle. By 1929, when many British students of armor were tending towards a pure armor formation, Guderian had become convinced that it was useless to develop just tanks, or even to mechanize parts of the traditional arms. What was needed was an entirely new mechanized formation of all arms that would maximize the effects of the tank.
The German tanks were not up to the standards of Guderian's concept. The Mark I was really a machine gun-armed tankette, derived from the British Carden-Loyd personnel carrier. The Mark II did have a 20-mm cannon, but little armor protection. Germany, constrained by the terms of the Treaty of Versailles, was not allowed to produce tanks of any kind and only a few armoured cars. In 1926 an unofficial program of tank construction was initiaited by Von Seeckt, the commander of the Reichswehr. Built by Rheinmetall-Borsig the first grosstraktor was similar to the existing British Mk II medium tank, 20 tons with a 75 mm gun. This and other designs were tested with Soviet cooperation at a tank school in western Russia. In Germany proper dummy tanks were used in training, apparently at the instigation of then Major, Heinz Guderian, a staff tactical instructor. Guderian had read Fuller, Liddell-Hart and other tank warfare theorists and he had the support of his commanders to develop his theories into reality. In 1931 the German General Staff accepted a plan for two types of tank, a medium tank with a 75 mm gun and a lighter vehicle with a 37 mm gun. While design and then construction work was carried out the German army used a variety of light tanks based on the British Carden-Lloyd chassis. The early tanks were code-named Landwirtschaftlicher Schlepper (La S), a designation that lasted until 1938. The first of these light tanks ran in early 1934, a five-ton Krupp design it was dubbed the LKA1. The new government approved an initial order for 150 in 1934 as the 1A La S Krupp, around 1500 of these light tanks were built.