It makes the distinction between a winner’s game (where you win by winning) and a loser’s game (where you win by not losing).
He argues that investing has become the latter but does offer some advice:
(1) play your own game – “Impose upon the enemy the time and place and conditions for fighting preferred by oneself.” Simon Ramo suggests: “Give the other fellow as many opportunities as possible to make mistakes, and he will do so.“
(2) keep it simple – “Play the shot you’ve got the greatest chance of playing well.”
(3) concentrate on defence (selling) vs. offence (buying).