The opportunity of defeating the enemy is provided by the enemy himself

Sun Tzu, in The Art of War: «To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself» (Book IV, Lionel Giles' translation).

In other words, however unbeatable your position looks to you, victory depends entirely on the context. And not only whether you win – your odds of winning depend on it too.

Poker makes you think about this every minute, and the quality of that thinking drives the money more than the cards do.

Here are three hands and the three duels between them. Ace-king loses to a pair of fives. The pair of fives loses to ten-nine suited. And ten-nine suited loses to ace-king. Rock, paper, scissors: among these three there is no strongest hand at all.

None of those percentages is an estimate. Each comes from enumerating all 1,712,304 ways the five shared cards can fall. There is nothing to argue with – and nothing to lean on either, because they are not a property of the hand.

In a real hand it is harder still. You are not playing against two specific cards but against every hand the other man could have arrived here with; against two players, two such sets at once. You cannot see his cards, so reading the context stops being a mathematical problem and becomes a question about what this person has done so far and what follows from it.

It is very good training. It teaches you to treat the «cards» life and business deal you as neither a sentence nor a guarantee.