Friday, January 12, 2007

Backgammon and Poker, Part 2

Backgammon is easily as aggravating as poker can sometimes be, and it seems perhaps more so. I don't know if they call it a suckout when a player who is very far behind lucks into a win, or if backgammon players tell "bad beat stories", but whatever the terminology is, the nature of the game is the same.

The backgammon equivalent of "rivering" someone is coming from behind in bearing off (when all the checkers are "free" of one another and each player begins removing them from the board according to dice rolls, with the winner getting his/her's off first.) I won't go into detail but let's just say that rolling doubles (6-6, 5-5, etc) is generally very advantageous.

Now with 36 possible ways to roll a pair of dice, and 6 of those ways being doubles, we can say the odds of rolling doubles are 5:1 against. Pretty long, but with the average bear-off requiring something like 6-9 casts of the dice, well, you should roll doubles at least once. Yet I have seen game and again where I was comfortably ahead, and my opponent rolled 3 sets of doubles, sometimes consecutively, to win. Odds of 3 consecutive doubles? 125:1 don't commonly see odds like that in poker, I can tell you that.

But maybe... Let's say player one holds 99 and player two has AA and the flop is 994. Player two needs running Aces, which is 22.5:1 to hit one on the turn and then 45:1 to hit one on the river. Unless I'm a moron and can't do odds anymore, that's a combined probability of over 1000:1 or something like 0.1%. I'm sure it's happened to some poor guy at one time or another.

Another common scenario involves your opponent needing exactly one number to do very bad things to you, like for instance he must roll a six, or you will likely win. Again, with 36 ways to cast two dice, 11 of them will include at least one 6, so the odds are about 2.3:1 against. Consider it a common A6 vs 88 70/30 matchup in poker.

Thinking (and rambling) about these kinds of probabilities -- and perhaps this is the point -- shows how the two games are similar yet different. NLHE allows a player to deny the other(s) the odds they will need by varying bet and raise sizes accordingly, but there is a problem: he doesn't have complete information. In other words, though you can control the pot odds, you must infer and guess at what those odds should be to make your opponent be in error to call, and that's if you are ahead with the best hand, which you also are often uncertain of. (Incomplete information is why bluffing is possible.)

On the other side, backgammon is a game of complete information. You know your position and your opponent's at all times. But (excluding the doubling cube, which is going into too much detail for a poker blog) you don't really "bet" to deny your opponent odds, and you often cannot force him to resign (like folding): he gets his turns and consequently, often gets his chance to suck out, no matter how far behind he may be. You must use the odds much more subtly, using probabilities of certain occurrences to guide your strategy and moves in a more indirect way.

Putting this all together, poker becomes more psychological because of incomplete information, and a good deal of the time involves looking backward in a hand to infer information and guide decision-making. Backgammon on the other hand relies heavily on examining countless future scenarios and balancing these rather complex possibilities with the current position.


Post a Comment

<< Home