All poker tables in casinos and sometimes also in home games have table stake rules that require each player to start each deal with a certain amount of money that can not be reduced or increased otherwise than placing it in the pot. In other words, players can not remove or add money from their pocket while the game is in progress. The stake of each player must be placed on the table and be visible to all other players. If the stake of a player ends up during the game and he can not call or raise, he certainly can fold, but he also can follow on of the rules below to solve such situation.
All In
If a player can not call a bet because he does not have enough money in the stake, he may go all-in, which means to place all the money has and to stay out of the betting action until the showdown, as if he called all subsequent bets. If such player wins the game, he wins money in accordance to the total bet he has placed. To make the process easier, the bet of all-in player is placed directly to the main pot, while other players, who continue betting according to the game limits, place the amount equal to the all-in players bet into the main pot and open a side pot, where they place the rest of the money of this and subsequent betting rounds. On the showdown, all players, but the one who went all-in reveal their card, and the player with the best hand among them wins the side pot. After that the all-in player reveals his hand, and if it is better than all others he wins the main pot.
An Example:
Jack, Charlie, Kate and John start the game when Charlie has only 5 dollars in his stake. Jack bets 20 dollars. Charlie wants to call it, but does not have enough money and goes all-in. He places his 5 dollars. Kate calls 20 dollars and John raises to 40 dollars, after which Jack calls, Charlie calls virtually (he keeps his hand without placing any money) and Kate folds. The round is over. Jack and John have placed 40 dollars, Kate has placed 20 and Charlie has placed 5. 5 dollars are taken from Jacks, Johns and Kates bets each and are placed in the main pot together with Charlies bet, so 20 dollars go to the main pot, while the remaining money (35 dollars from Jacks bet, 15 dollars from Kates bet and 35 dollars from Johns bet) opens a side pot. All bets in all further rounds of the game are placed in this side pot. On the showdown, Jack and John reveal their hands. Jack has a pair of 7s, and Jack has a pair of kings. Jack wins the side pot. Charlie reveals his cards. If he has a hand better than two kings, he wins the main pot, otherwise it also goes to Jack.
Usage:
All-in can also be used to raise, but such raise is treated according to the limits of the game. Pot limit and no limit games always use the full bet rule, while fixed limit or spread limit games use either the full bet rule or the half bet rule. Minimum raise amount in a game with full bet rule is equal to the minimum bet, while in a game with the half bet rule it is equal to half of the minimum bet. If the raise made by the all-in player is smaller that this value, such raise is considered a call of a higher size, which means that all other players, of course, must equalize this bet as if it was a raise, but the all-in player is not considered to be the last to raise. The last raise is credited with the player who raised or bet before the all-in player, so if all other players call, this player can not reraise the bet, and the round is over.
If all players or all but one player at the table go all-in, no further betting can take place. If such situation happens at poker tournaments, all players reveal their hole cards and all subsequent cards are dealt face up.
Open stakes rule is only use in home games. Players of a game with open stakes are allowed to buy more chips during the game, borrow chips from other players or bet with an IOU (I owe you) certificates called Markers. Markers can only be used if all players at the table allow using them. If one or more players refuse to use markers, another solution must be used. The player who wins the pot may either request the debt by the marker or use it in the further betting. Open stakes rule does not cancel the all-in rule, so players can always go all-in instead of borrowing money or buying chips, but if a player adds or borrows money to raise, he can not go all-in in the same game.