The Panzer IV was the brainchild of the German general and innovative armored warfare theorist Heinz Guderian. In concept, it was intended to be a support tank for use against enemy anti-tank guns and fortifications. Ideally, each tank battalion in a panzer division was to have three medium companies of Panzer IIIs and one heavy company of Panzer IVs. On 11 January 1934, the German army wrote the specifications for a "medium tractor", and issued them to a number of defense companies. To support the Panzer III, which would be armed with a 37-millimetre (1.46 in) anti-tank gun, the new vehicle would have a short-barreled, howitzer-like 75-millimetre (2.95 in) as its main gun, and was allotted a weight limit of 24 tonnes (26.46 short tons). Development was carried out under the name Begleitwagen ("accompanying vehicle"), or BW, to disguise its actual purpose, given that Germany was still theoretically bound by the Treaty of Versailles ban on tanks. MAN, Krupp, and Rheinmetall-Borsig each developed prototypes, with Krupp's being selected for further development.
During its production run from March 1942 to June 1943, the Panzer IV Ausf. G went through further modifications, including another armor upgrade which consisted of a 30-millimetre (1.18 in) face-hardened appliqué steel plate welded (later bolted) to the glacisÐ Ð†Ð â€šÐ²Ð‚Ñœin total, frontal armor was now 80 mm (3.15 in) thick. This decision to increase frontal armor was favorably received according to troop reports on 8 November 1942, despite technical problems of the driving system due to added weight. At this point, it was decided that 50% of Panzer IV production would be fitted with 30 mm (1.18 in) thick additional armor plates. On 5 January 1943, Hitler decided that all Panzer IV should have 80 mm (3.15 in) frontal armor. To simplify production, the vision ports on either side of the turret and the loader's forward vision port in the turret front were removed, while a rack for two spare road wheels was installed on the track guard on the left side of the hull. Complementing this, brackets for seven spare track links were added to the glacis plate.
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