Double or nothing (UK often Double or quits) is a gamble to decide whether a loss or debt should be doubled or cancelled. It refers to the potential outcome in a betting situation where the winner risks what has been won for a chance to double their winnings. If the loser of the initial bet loses again, then the winner gets double the original bet. But if the loser of the initial bet wins, then he/she owes nothing, and receives double - hence Double or Nothing. For example, if one owes somebody a glass-bottle Coke from a bet and then places a "double or nothing" bet with the same opponent, they will either owe two glass-bottle Cokes if they lose again (double the original amount), or if they win, they owe nothing. Correctly played however, in a higher-risk double-or-nothing situation, the loser of the original bet may offer a "Double or nothing," to which the winner of the first bet can decline or accept. In this case, the prize, or amount both players put into the bet, is doubled by each player, and the original bet is void. Both players again have the same chances of winning the doubled prize.
In poker, a double or nothing tournament is an online sit'n'go tournament where the surviving half of players gets double the buy-in and the eliminated half does not receive any prizes. Double or nothing tournaments are mostly played by ten players (five players win) or six players (three win), although multi-table versions, such as for 20 players, exist. The rake in these tournaments is usually smaller than in standard sit'n'go tournaments. Some poker rooms also offer triple or nothing tournaments, where one third of the playing field gets paid.
In a regular poker sit’n’go it is correct to play with the intention of accumulating 100% of the chips in the game, thereby placing 1st and securing for yourself the maximum possible prize money. In a double or nothing poker sit’n’go it is now no longer relevant if you finish the game with 100% of the chips or only 1% of the chips, as long as you are still in the game once 50% of the players have been eliminated. Because of this difference in prize structure, a double or nothing poker sit’n’go requires significantly different poker strategy than a regular poker sit'n'go.