At the beginning of the WW2, German forces gained notoriety for the rapid and successful invasions of Poland, the Low Countries, France, and the Soviet Union. Although the early panzers were in some respects inferior to some of their French and Soviet counterparts, the Blitzkrieg was made possible by the German military experience in WWI, their level of training, integrated communications, coordinated use of airpower, and, perhaps most famously, by the combined-arms employment of integrated infantry and armoured forces, the panzer divisions.
Later in the war a new generation of big tanks, the heavy Tiger, Panther, and King Tiger tanks were developed and rushed into the battlefield. The Soviets continued to produce the medium-sized T-34 by the tens of thousands as well as introducing the heavy Iosef Stalin (IS series) tanks, and U.S. industry nearly matched them in the number of M4 Sherman tanks built and deployed in Europe after D-Day.
Throughout the war, the panzer was a key piece of the combined arms doctrines supporting the German Blitzkrieg. The tanks were used in almost every theatre of German involvement. Their largest engagement occurred at the Battle of Kursk, which saw about three hundred panzers pitted against five hundred Soviet tanks.