according to my intuition, if you commit no mistake and play only excellent moves, then you can't lose the game. if both players make only excellent moves, then there is a draw. there must be a mistake somewhere to allow a mate. but is this just common sense, or is there some mathematical demonstration proving that this intuitive rules are true?
some theory
Sort:
"one player can play 40/40excellent moves, and lose the game because of only one mistake against someone who made 10 mistakes".