The light tanks Pz.Kpfw I and Pz.Kpfw II made it possible the German industry of war to be made a good experience. It was not from now on to depend any more on the foreign achievements. The staff officer specialist in the armoured tanks, the General Guderian, recommended the realization of 2 types of tanks of battle in order to equip future Panzerdivisionen. According to him, the first model was to be armed with a gun firing perforating ammo, a machine-gun of hull and a machine-gun on turret. The second model, considered as a support vehicle was to be armed with a gun of larger gauge with low initial speed. The first of these two machines, Pz.Kpfw III was in theory to equip the three light squadrons in Panzerregiments.

The armament of Panzer III, divided appreciably the higher realms, the Ministry for the armament supporting the gun of 37mm while the Inspection of the motorized troops supported the gun of 50mm. As the infantry was mainly equipped with the gun of 37mm, in an aim of standardization, it was this gun which was selected. However the circular of the turret was to be able to allow later on the installation of a larger gauge.

Krupp's prototype, the MKA.

src: site "Achtung Panzer"

Because of the limitations of circulation on the roads and the bridges, the maximum weight of combat was fixed at 24 tons for Panzer III and Panzer IV. A maximum speed on road of 40 km/h was necessary. The crew of 5 men was composed like such: a commander, a pilot, a radio-machine gunner, a gunner and a loader. Throat microphones were to allow the interior communications between tanks during the progression.

In 1935, the Service of the armament of the Army (Heereswaffenamt) solicited the firms MAN, Daimler-Benz, Rheinmetall-Borsig and Krupp for the development of Panzer III under the cover name of Zugkraftwagen (tractor). Since 1936, prototypes were subjected to thorough tests. It is ultimately the model of Daimler-Benz which will be selected. The first tank will be manufactured by Daimler-Benz, the same year. This model will be tested during tests of corps of troop under designation 1/ZW. The suspension of the 1/ZW was a experimental type with five great supports of double road wheels with helical springs. This machine of approximately 15 tons had a maximum shielding of 14.5mm and was propelled by one 12 cylinders Maybach DSO 108TR high performance (11 L of cubic capacity) providing a power of 250HP and a maximum speed of 32km/h. This tank carried 150 rounds of 37mm and 4500 rounds for its three machine-guns, which two were coaxialy assembled with the gun in the turret. This first model received the semi-official name of Pz.Kpfw III Ausf.A.