I am puzzled over this thread. It doesn't matter where the battle was. From '42 onwards the Red Army was coming to grips with the German Wehrmacht. The endresult would have been the same no matter where they fought. So I'd say that the most important battle was sorting out the clutter in STAVKA.

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'We march. The enemy is retreating in transport. We follow on foot.' Lt.Neil McCallum 5/7 Gordons 19th November 1942