All games

BS

Also known as Cheat, I Doubt It, Bullshit, Doubt It

Players
2-10 players (best with 5)
Deck
1 standard deck (52 cards), jokers removed; 2 decks shuffled together for five or more players
Time
15-30 minutes
Difficulty
Simple
Category
Bluffing

Setup

Take the jokers out. One pack does for four players or fewer; from five up, most tables shuffle two together, which doubles the number of each rank in play and so changes what a large claim means.

Two can play, but the game is thin at that size: with only one opponent you know exactly where every card you do not hold must be, and there is almost nothing to hide. Four to six is where it works.

Pick a dealer any way you like; the deal passes to the left afterwards. Deal the entire pack out one card at a time, clockwise, until nothing is left. Hands will not come out even unless the player count divides into 52, and that is fine: a one-card difference has no effect. With four players everyone starts with thirteen.

Pick your cards up and sort them by rank. You want to be able to see at a glance how many of each rank you hold, because the whole game is a running calculation of what you can honestly play and what you will have to fake.

Leave the middle of the table clear for the discard pile. It starts empty and can grow to most of the deck.

The player to the dealer's left goes first and must claim aces; some accounts simply pick the first player at random. Play runs clockwise.

Play

Ranks are claimed in a fixed ascending cycle: ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, jack, queen, king, then back to ace and around again. The cycle belongs to the table, not to any player. Whatever rank the previous player claimed, you claim the next one up.

On your turn, put anything from one card upwards face down on the pile and say aloud how many and of what rank — "two nines", say. The rank is dictated by the sequence. The number is up to you, and so is whether the cards are actually what you said. You may play any cards you like under any claim.

You must play at least one card. You cannot pass and you cannot play zero. This is the engine of the game: sooner or later the sequence reaches a rank you hold none of, and you have to lie.

Nothing in the rules caps the number, but the pack does the capping for you: with one deck there are four of each rank and with two there are eight, so a claim of five in a single-deck game is not against the rules — it is simply a lie nobody has to think about.

Once your cards are down, any other player may challenge by calling "BS!" (or "Cheat!" or "I doubt it!"). The window stays open until the next player's cards hit the table, at which point the claim stands for good. Only one challenge is ever resolved, and it is the earliest one. Two people calling half a second apart is settled by ear, and for a genuine dead heat no published rule set offers a ruling at all, so agree a tie-break before you deal rather than during one.

A challenge is resolved by turning over only the cards that were just played, not the whole pile:

"The pile" means every card in the middle, including the cards that were just turned face up, and all of it goes into the losing player's hand. The rest of the pile is never exposed, so only the cards from the challenged play become public knowledge — though some groups turn the whole pile face up instead, which tells everyone who has been lying and for how long.

Either way the pile is now gone from the table and the next player starts a fresh pile. Picking up does not cost you anything else, and it does not skip anyone.

A challenge does not reset the rank cycle and does not change whose turn is next. Play carries on with the player to the left of whoever just played, claiming the next rank up, no matter who ended up with the pile. If the last claim was eights, the next claim is nines even if the eights turned out to be garbage and their owner is now holding twenty cards.

If nobody challenges, nothing is revealed. The cards stay face down on the pile and their true identity is never learned, which is exactly what makes the game work: a successful lie is invisible.

Going out has one wrinkle. Playing your last cards does not finish you immediately; you are only out once the challenge window has closed. If someone calls BS on your final play and you were lying, you take the pile and you are back in the game with a fistful of cards. If you were telling the truth, the challenger takes the pile and you have won. If nobody calls, you are out and the game ends there.

Goal & scoring

You are trying to empty your hand. Get the last card down and survive whatever challenge it draws, and the game is yours.

There is no point scoring at all. A game is a single deal and takes as long as it takes.

Many groups do not stop at the winner. Once someone is out, the rest keep going and note the order in which they finish; whoever is left with the only unplayed hand at the end takes last place. Anyone who has already finished is passed over on later circuits, and the rank sequence continues from wherever the last claim left it rather than starting over. Ranking the whole table this way keeps the people still in it invested after the first person leaves, and it turns second-to-last into an outcome worth chasing rather than a consolation.

A few practical points that decide games. Lie small: claiming one card is far less suspicious than claiming four, and it also costs you less to be caught early when the pile is short. Watch the pile size, because a challenge is only worth making when the pile is small or when you are certain. And count: if you hold three queens yourself, anyone claiming three queens is caught before they finish the sentence.

Variants

Free choice of rank (Bluff) — Instead of a fixed ascending cycle, the player who starts a pile names any rank they like, and every player after them must claim that same rank until a challenge happens. Whoever ends up taking the pile starts the next one with a rank of their own choosing. This removes the forced-lie pressure of the ascending version, since you can open on a rank you actually hold, but it makes reading other players harder because nobody is ever obliged to lie. This is the version usually meant by the names Bluff and I Doubt It in older books.

Restricted challenge window — Rules differ on who may call and for how long, and no published account settles it. One version lets any player call until the next player's cards touch the pile. A tighter house rule allows only the player to the immediate left of the one who played, which keeps the game fast and stops the whole table ganging up. A looser one lets anyone call at any point before the pile is next collected, so a claim can be caught several turns later. Settle this before dealing; it is the single most argued-about rule in the game.

Lying about the count — Some groups let you cheat on the number as well as the rank — say "three eights" while putting down three eights and a jack, and hope nobody counts. It is challenged in the ordinary way and caught in the ordinary way, but it turns every claim into two things to check rather than one, and it makes a fast, confident delivery worth a great deal more.

Downward and either-way sequences — The ascending cycle is not the only one in print. Some tables run it downward instead, opening on aces and going A, K, Q, J and on down. Others let each player choose the next rank either above or below the last call, and some add the option of repeating the same rank, which gives three choices a turn. Every loosening of the sequence makes honest play easier and lies correspondingly rarer, and each one kills the standard tactic of counting ahead to work out which rank is about to land on you.

Two-pack table — For five or more players, shuffle two 52-card packs together. Everyone still gets roughly the same hand size, but each rank now has eight copies, so a claim of five or six is no longer self-evidently false and the arithmetic of catching a liar changes completely. Holding three of a rank no longer proves much. Piles grow much larger, which makes getting caught genuinely punishing.

Rules checked against Pagat, Bicycle Cards, Wikipedia, Official Game Rules, Game Rules, Denexa Games, PlayingCardDecks, Gambiter.