A string bet is a term used in the game of poker and is best summarized as a "delayed raise". This move is considered illegal in live games (house rules may vary). To get a better understanding of a string bet, I'd like to explain the two types of legal raises in a poker game.
- Announce the raise. When a bet has been made and you would like to raise, simply say "raise" when it is your turn to act and bring your chips to the pot.
- Bring all the chips to the pot at once. In one motion, bring all the chips needed to call the bet and make the raise. In this instance, a verbal indication is not needed.
A string bet then could be done basically in two ways. Hollywood has a way of glorifying the, "I see your bet and raise you..." phrase. In live games, this wouldn't work. As soon as you call, you can no longer raise.
The other way to make a string bet is to put your chips out to call the bet, and then reach back for more chips to make the raise.