The PANZER IV Tank was the backbone of the German tank force. Deployed in various versions, its armament was continually improved and adapted to the demands of tank warfare. Along with this model, the PANZER II and PANZER III tanks were also deployed at the start of the Eastern Campaign. The inadequate armament of the PANZER II led to its rapid retraction. The PANZER III was strengthened by the mounting of a 5-cm gun and partially through the installation of a 7.5-cm short-barrel gun, but could still be seen only as temporary solution with limited capabilities. This only changed radically with the deployment of the heavy tank generation of TIGER and PANTHER tanks. Air-plane " H" Alphabet caused Germany tank what concurrent waren't.