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BS strategy

posted 2023.12.18
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I’ve played BS a handful of times, and I don’t think anyone plays it very strategically. This makes sense, because it’s a card game for 12-year-olds that’s more about making funny bluffs1 than actually winning. But there is a strategy to it.

Rules recap

Play with 3+ people. Ideally 4-6. Pick a starting player and deal an equal number of cards to every player. Then the starting player plays N cards from their hand face-down and says, “N aces”. Anyone else can say BS. If they do, reveal the N cards the starting player played, and if they were aces, the BS-caller takes the pile. Otherwise the person playing the aces takes the pile. This continues clockwise through the ranks. The person to their left plays twos, then the person to their left plays threes, and so on. After reaching kings, cycle back to aces. The game ends when someone runs out of cards.

Example game:

The strategy

It’s predetermined what ranks you will have to play. The starting player in a four-player game will always have to play aces, then fives, then nines, then kings, then fours, then eights, and so on. Know those ranks so that when you bluff, you know which cards you will need soon.

The second strategy pertains to when you should call BS. This will partly rely on your read of whoever is playing, but it also depends on how high your risk tolerance should be. Calling BS is a risk, and calling it on a bigger pile is a bigger risk (with a bigger potential reward). Here’s what determines your risk tolerance:

If you have a lot of cards, you might end up with enough to guarantee that a person’s claim is wrong (say, if you have all four jacks). Likewise if someone plays four cards at once, don’t call it unless you can disprove them, because if they’re lying then someone must have proof.

If you’re really good, I think you could count cards. Not perfectly, but if someone calls BS on two sevens and is wrong, you at least know they have two sevens. But I don’t think it would make a big difference.

How much can you win like this?

The average player of this game is not even paying attention to what other people play half the time, so just by doing that I think you have a slight advantage. And if you execute this strategy well I think you would have a large advantage over average player, maybe winning half the time in a four-person game. I don’t think that hard when I play and from a small sample size I think I win more than my fair share, but it’s hard to tell.

I would be curious to see how the game would look if everyone played it strategically. I think there would be fewer very short games (because anyone with an early lead would get BS called on them more often) and fewer very long games (because within a few turns everyone would have an endgame plan). I would like to make bots to do this, but game theory is hard so instead I’ll just think about it.

  1. The funniest bluff, in my opinion, is saying “three sixes,” then playing five cards because nobody’s paying attention.