A string bet is an illegal bet where a player essentially makes two declarations to make one bet. It is either...
- When a player uses more than one forward motion to put chips in for a raise without verbally declaring the raise first.
- When a player verbally states, "I see your call...and I raise", without putting the full bet in first.
String betting can also be a form of angle shooting where a player attempts to gain an advantage by gauging their opponent's reaction to the call. The idea is that a player could call, then try and read the opponent's response, then based on the reaction, elect to raise or stick with the call. The dealer will determine where to draw the line, but if you suspect that somebody is employing this tactic, you should learn to defend yourself by calling a person on it when it happens. Don't be too quick to accuse somebody of deliberate string betting though, because it is a common accident, and nobody likes being unfairly accused of cheating. If you are certain that they are doing it on purpose, you may want to watch that person for other signs of cheating.
As a dealer, it's important to remember that string bets will be an accident the vast majority of the time. Since it is common for players to do this, so you should remind them to use one forward motion when raising. Now the question is what to do with their sloppy bet. If the player said the cliched "I call...and raise", then it is just a call. If the player made two forward motions, the result depends on first motion...
- If a single large chip is thrown in, it is a call according to the "oversized chip rule", this supersedes the following bet-size rules.
- If the first forward motion is less than half a legal raise, then it is a call and the player is refunded the extra amount.
- If it is between half a legal raise and a minimum raise, then the player must complete a minimum raise.
- If it is a regular raise then it counts as that raise and can't be increased to a larger raise.
- Remember to only include the first forward motion of chips, additional motions should always be refunded.
For reference, Robert's Rules mentions string betting under 'betting and raising'. Here's the quote:
14. String raises are not allowed. To protect your right to raise, you should either declare your intention verbally or place the proper amount of chips into the pot. Putting a full bet plus a half-bet or more into the pot is considered to be the same as announcing a raise, and the raise must be completed. (This does not apply in the use of a single chip of greater value.)