I am reading (and enjoying) Robin Cross's book "The Battle of Kursk" and he includes an interesting quote. "It is very likely that it was teh only occasion in Military History when the stronger side, having the capability for offensive action, went over to the defense. The future course of events affirmed that, in the given instance, the correct decision was made". Pretty ingenious if you ask me. Let the other side exhaust themselves and then just as they are faltering, throw your own forces against them!