SpillpratBordspillBlackjackWhat is the trick to the 21 game?
What is the trick to the 21 game?
hey, my uncle just taught me this game where you take turns saying 1, 2 or 3 numbers, start at 1 and count up, and whoever says 21 loses. i lost five in a row to him. tried mixing up my counts, letting him start, everything. is the game rigged or is there actually a trick to it? (and no, there are no cards involved, even though we call it 21.)
The trick is to force your opponent to say 21, and you do that by making every one of your turns end on a multiple of 4: 4, 8, 12, 16, 20. Since you can say 1, 2, or 3 numbers, whatever they say, you can always reply with the gap that lands you on the next multiple. If they say 2, you say 2. If they say 3, you say 1. They're on 17, they say 3, you say 1, and the total hits 20. They then have to say 21, and they lose. That's the whole game.
So the real trick is to go first, because that's the only way to guarantee you get to 4 before they do. Say 1, 2, or 3 yourself, hit 4, and then never let go of the multiples. If your opponent goes first and they know this, you're done before you start. They'll park you on 20 and there's nothing you can do. The game is purely about who controls the number 4.
It's a Nim game, that's the category if you want to read more. The losing positions are the numbers one less than a multiple of 4, and the winning moves are always the ones that leave your opponent facing a multiple of 4. Same logic applies to 31, 50, whatever target you pick.
And yeah, it has nothing to do with counting cards or blackjack, which is what you'll find if you search "21 game" and get a casino. This is just a pure arithmetic trick. The one thing that catches people out, including your uncle if he taught you this, is that it falls apart the second the starter makes a mistake. If they forget and let the total drift off the multiples, you can steal it right back.
Pit boss before the oil crash. House edge is my business.
It's a losing game for the second player, full stop. If they know the trick, they go first. If they don't, you say 1, 2, or 3 to land on 4 and then park them on every multiple. The only way you win as second player is if the starter screws up. So the real trick is being the one to say "I'll start."
20 winters of dealing in the north. The cold keeps the cards still, but the players don't.
Same strategy carries over to the dice version, if anyone brings that up: roll a die, add to a running total, target 21, and the winning moves are the same multiples of 4. The loser is the one forced to push the total past 20.
Counted cards in Vegas before the casinos banned me from three of them. Still count groceries.
Played 20 rounds against a mate who also knew the trick once. The starter won all 20. Every single one. If both of you know the multiples of 4, the second player has zero chance unless the starter slips. And they usually do slip after a few rounds, so if you're stuck going second, just wait for them to forget to leave you on 16, then take it.