Army Group Center and Army Group South of the Wehrmacht planned to capture the area around the Russian fortress city, Kursk through the method of a double pincer envelopment, spearheaded separately by AGC's 9th Army, commanded by General Walter Model, and AGS's 4th Panzer Army, commanded by General Hermann Hoth. This plan was called "Operation Citadel".
The Campaign initiated at the morning of July 5, 1943. From the south bulge of the salient, Hoth's troops made their way towards their objective beyond Kursk to meet Model's men, who are breaking through from the northern sector. Soviet resistance was fierce, so the German advance got weakened 'til they halted. Hoth has reached further than Model. Around the area of the 4th Panzer Army, huge numbers of armored vehicles from both sides clashed in probably the biggest tank battle in history, near the town of Prokhorovka. Many casualties were inflicted on both sides, the Soviets had a quantity advantage but lost more men, but the Germans couldn't sustain their war materials enough to keep up the offensive. They lost more than they gained this year, and the Western Allies had just invaded Sicily, so Citadel was called off and the Germans retreated.