Its amazing that someone could beat a computer that was professionally programed like Deep Blue was even once. When you consider how may move possibilities it can process in one second in comparison to mans capabilities to process moves, its boggles the mind to rationality contemplate ever beating it. And I still don't understand how its ever done. I believe it has to do with "sacrifice", but even then wouldn't that be considered a possible move variation and be considered as a possibility by the computer? Since the game has no 'chance' factor to consider, it would seem to me that EVERY move could be considered, even a "sacrifice" that is just another s strategic move in a chain of many.