Recently there was some discussion on the poker newsgroup RGP concerning the correct rule when determining whether or not an all-in bet should be considered a valid bet. This is one of those rules that has different variations, and many poker rooms use different interpretations of what the "correct" rule should be.
When determining whether an all-in bet should be considered a valid bet, the "half-or-more" rule is the most common (and correct) one used. This rule states: "An all-in wager of a half bet or more is regarded as a full bet, wherein another player can fold, call, or make a full raise."
The situation: It is a $20-$40 hold'em game with five-way action preflop. On the flop, the player under the gun checks. The next player goes all in for $10 (half of a full bet). The half-bet is called around the table until the action gets back to the player under the gun, who check-raises.
Immediately, two players yell out that he cannot check-raise an all-in player. The dealer asks the check-raiser if he wants a decision from the floorman.
The check-raising player definitely should have asked for a ruling. He would have received the correct ruling that since the bet was half or more, he would be allowed to raise. In this case, the other players at the table convinced him that a ruling would go against him and he took back his raise.
Think of it this way: When a player acts on his hand with a check or a bet, he is either passing the action or taking betting action. When a player has the same options but doesn't have a full bet (that is, will be going all in), he also is either passing or taking betting action, depending on the amount of chips he has left. Let's take a look at different scenarios on the flop in a $20-$40 hold'em game:
Player A has $6 left, and it is checked around to him. He can either bet the $6 or check. In this case, no matter what he decides to do, his action is going to be treated as a check. If he bets the $6 (which is less than half of the legal bet), all other players who have previously acted on their hands will only be able to call the $6 or fold.
Player A has $11 in front of him, and it is checked around to him. If he bets the $11, it will be treated as a full bet (half or more) and the betting that follows will proceed accordingly. The next person to act will have the option of calling the $11, folding, or raising $20 to $31.
The half-or-more rule is used in almost all poker rooms today. There are a few exceptions, and these are usually rooms that have been around for a long time and haven't gotten around to changing their rules, or are run by a manager who isn't thinking clearly when evaluating this rule. The half-or-more rule has been around for a long time, but there were many rooms that didn't use it years ago.
Like many rules in poker, there is one exception to the half-or-more rule. In no-limit and pot-limit games, the half-or-more rule does not apply. The correct rule in these games is: "A player must raise the full amount of the previous bet to reopen the betting." The reason for the different rules for the different games is somewhat complicated. The no-limit/pot-limit rule basically protects players from a situation in which someone is allowed to reopen the betting on a relatively small bet in order to be able to isolate players. Because of this rule, it is important when playing no-limit and pot-limit games that you pay attention to your opponents' stacks.
Editor's note: Michael O'Malley can usually be found playing online at partypoker.com as Rzitup. To learn more about him go to www.rzitup.com.