In a game of poker, once a hand is in play the casino rule is that a player cannot add to his chips. During this hand, if he bets the last of his chips he is “all-in.” The dealer usually places an All-In button in front of him. This happens so often, a side-pot is established on the board where all subsequent chips bet are placed. The all-in player remains in the hand only for the main pot. There could be more than one side pot.
The presence of an all-in player can substantially influence the results in two ways. Let’s explore this with two typical hands while playing limit Texas hold’em.
You are dealt a strong hand – Qh-Qs, a “made” hand. You could win with this hand even without further improvement. You can hope to catch a set on the flop, but the odds are about 8-to-1 against it. More likely, your pocket pair will be the best hand you end up with.
After two opponents limp to see the flop, you raise it up from your late position. Three opponents stay to see the flop with you. Great so far. By thinning the field – the two blinds and the button are still in the pot – you have a much better chance your pocket Queens will prevail and take the pot even without improving. The flop puts three middle/small cards on the board, including two clubs: 5c-3c-8s.
That’s a good flop for you – no King, no Ace. You figure your pocket-Queens is still in the lead. It’s checked to you; so you open the betting, hoping to thin the field even further. Perhaps, all of your remaining opponents will fold, leaving the pot for you. Only the Big Blind (BB) calls to see the turn with you. It’s the 5h, putting a pair of fives on the board. The BB comes out betting. What could he have made? Perhaps he has trip fives, you reason. You just call his bet.
On the river, another Queen falls on the board: 5c-3c-8s-5h-Qd. Lucky you! You hold Queens-full-of-fives. Again, BB bets into you. Pondering for a few moments, you figure he probably has trip fives or a Queen in the hole for two-pair; at best he has fives-full-of Queens. Little does he imagine you could be holding pocket Queens for Queens-full-of-fives – almost the nuts.
Of course, you raise for value – to build “your” pot even bigger. But, then you realize BB went all-in when he opened the betting. You are somewhat frustrated, but happy to take a nice pot. However, had he not been all-in, very likely you could have built the pot much bigger with no limit on the number of raises allowed.
Starting with the same pocket Queens, again you raise before the flop to thin the field. The same three opponents call to see the flop with you. This time there is both a draw to a straight and a draw to a flush on the board after the flop. Your Qh-Qs remains an overpair to the board: 10c-8c-7d.
With this flop, an opponent could have a draw to a straight or flush. This time, the BB opens the betting – you figure him for a pair of tens. Now, you raise it up, hoping to protect your vulnerable overpair by thinning the field. However, the Button is all-in, so he cannot be forced to fold.
He is in the pot all the way, vying for the main pot. The turn is a blank. The BB checks to you, and folds after you make the big bet. Now, it’s just the all-in Button and you all the way to the showdown. No more betting. With just two-outs, he catches trip 7’s on the river; and takes the pot away from you – all because he was all-in, and could not be forced to fold.