People in the United States know very little about World War Two as it was fought in Europe. The real war in Europe was waged on the Eastern Front, after Hitler invaded Russia in the summer of 1941. At first, it was all blitzkrieg, with German victories on all fronts and horrendous Russian losses. Things began to change after Stalingrad, however, when the entire German 6th Army surrendered to the Soviets.
The next big battle was at the Kursk salient. Hitler and his generals planned to attack the salient from two sides, take Kursk, and trap several Soviet armies. This was the intent of Operation Citadel, as shown in the map below:
The German General Staff thought the Russians would take fright at the Nazis’ technologically superior tanks and surrender in droves. But the Russians—beginning with Stalin himself—learned their lesson in 1941 and 1942. In July 1943, Stalin realized he had more human and industrial resources to draw on than the Germans. This was similar to Ulysses S. Grant realization during the American Civil War when, after the Battle of the Wilderness, realized that he could afford to take more casualties than Robert E. Lee’s Army of Northern Virginia and still win.
Instead of pinching off the Russians in the salient, General Walter Model advanced only 10 miles on the north, where he was beaten by Rokossovsky’s Central Front. The real battle was in the south, where General Erich von Manstein battled with Nikolai Vatutin’s Voronezh Front over the town of Prokhorovka. Vatutin kept throwing rifle regiments, tanks, and artillery at von Manstein’s Army Group South until, after a 30-mile advance, the Germans could go no further.
The Russians had a very good idea of what the Germans were planning with Operation Citadel, and they had more men (at a 2.5:1 ratio) than the Germans, and more tanks (though not as good). So they planned carefully to fight to the last man, if necessary.
By the time Vatutin and Rokossovsky had finished with the German army, there was no more blitzkrieg. Hitler didn’t know it yet, but from this point his armies were in retreat.