This reminds me at a chessproblem I' ve seen about 15 years ago. It was a checkmate in 7 moves with a story behind it. Something about a man who plays with the devil with his soul at wager. After a long game the devil smiles and says 'in 7 turns I win - your soul is mine'. The man looks a the board and answers 'I'm afraid you are right but I want to play it to the end.' Seven turns later the devil does his move and calls out 'checkmate!'. A second later he vanishes without even taking the man's soul, why?
If you solve the chessproblem you see that in the final position the chesspieces form a perfect cross, so by making his winning move the devil banned himself.