Gin Rummy rules

Gin Rummy is a two-player card game played over a series of short hands. Each hand, both players try to arrange ten cards into melds and reduce the value of whatever will not fit. The first player whose leftovers are small enough may end the hand, and the difference between the two players' leftovers is scored.

A hand takes a couple of minutes and a match runs to 100 points, which usually means somewhere between four and ten hands — 10 to 20 minutes in total. Each turn has 45 seconds on it.

One standard 52-card deck, no jokers. A card's value is what it counts as deadwood at the end of a hand, and it is the same value whichever suit it is.

Aces are low and do not wrap. A-2-3 is a run; Q-K-A is not a run, and an ace next to a king is two separate cards worth 11 between them.

Ten cards to each player. Of the thirty-two left over, one is turned face up — that single card is the discard pile at the moment the hand starts — and the other thirty-one sit face down as the stock.

Only the opening is unusual, and it is unusual in one way: nobody has discarded yet, so the face-up card was chosen by the deal rather than thrown away by an opponent. Both players get the refusal of it, non-dealer first. Whoever takes it discards as normal and the hand is under way; if neither wants it, the non-dealer opens by drawing blind from the stock. The card the non-dealer refused stays where it is and is not on offer again.

In the first hand of a match the player who joined the table last is the non-dealer and opens, which makes the player who was already sitting there the dealer. This is the table rule the rest of the site uses — last to join, first to move — and Gin Rummy already agrees with it, since the non-dealer always opens, so no title needs an exception.

The winner of a hand deals the next one — after an undercut, that is the player who was knocked. After a hand that ends with the stock exhausted and nobody scoring, the same player deals again. Every hand is dealt from a freshly shuffled deck, so a hand that did not finish is never replayed with the same cards.

A turn is exactly two actions, in this order: draw one card, then discard one card. There is no turn on which you hold fewer than ten cards between actions, and none on which you may pass.

• Draw the top card of the stock, face down, which tells your opponent nothing.

• Or draw the top card of the discard pile, face up, which tells them exactly what you took.

• Then discard one card from your hand, face up, on top of the discard pile.

• You may not discard the card you just drew from the discard pile on the same turn.

Only the top card of the discard pile is available. The cards under it are out of the game, though both players are free to remember them.

A meld is three or more cards that belong together, and there are two kinds.

Each card is spent once. The 4♠ in a hand holding 4♠ 4♥ 4♣ 2♠ 3♠ can finish the set of fours or the run up from the two, never both, and whichever it does the other two cards are deadwood: 2♠ and 3♠ count 5 after the set, 4♥ and 4♣ count 8 after the run. Take the set, and it is three points, which is the margin a knock is usually decided by.

Deadwood is every card in your hand that is not part of a meld, added up. It is the number the whole game turns on: it decides whether you may knock, and the difference between the two players' deadwood is the score.

Your melds are worth nothing in themselves. A hand of three melds and one leftover king counts 10; a hand of two melds and four small cards may count less.

After drawing, and only then, you may knock if your deadwood totals 10 or less. You knock by making your final discard face down instead of face up, and by showing how your ten remaining cards divide into melds and deadwood. Both hands are then laid out and counted.

Knocking is never compulsory. A hand under the threshold may keep playing to improve, and that is often the right choice — and often not.

You must meld everything that can be melded: a leftover card that fits one of your melds (a fourth eight, the next card of a run), or three leftover cards that make a meld of their own, cannot be kept back as deadwood. Where the same cards can be divided more than one way — a set of fours or a run through one of them — the choice of division is yours, and it is a real one, because a set can be laid off onto less than a run can.

You cannot knock before drawing, and you cannot knock on the turn you take a card and put it straight back. You can knock on the very turn that would otherwise have ended the hand with the stock down to two cards.

Gin is a knock with no deadwood at all: all ten cards in melds. It pays a 25-point bonus on top of your opponent's deadwood, and — this is the part that matters — your opponent may not lay any of their deadwood off onto your melds.

Big gin is eleven cards in melds, which happens when the card you draw completes the hand without a discard. It pays 31 instead of 25, and the same no-layoff rule applies. You knock on it without throwing anything. If you hold eleven melded cards you may instead throw one and go ordinary gin, but that pays 6 less and there is rarely a reason to.

Neither gin nor big gin can be undercut. An opponent whose own ten cards all make melds counts nothing, and you are still paid the bonus on top of nothing.

When you knock with deadwood — anything other than gin — your opponent may add their own unmatched cards to your melds before counting. A fourth eight onto your set of three, a 9♣ onto your 6-7-8♣: those cards stop being their deadwood.

This is why a knock can go wrong. The hand you knocked on is the hand they escape into, and laying off is what turns a comfortable margin into an undercut.

Laying off is done for the player who is answering, not by them. Nobody is asked which cards to lay off, because it is never a decision: whichever cards go down, the cards left over are counted as a hand that melds itself as well as it can, and the combination that leaves the lowest count is the one that is used. A card is never laid off if keeping it in a meld of your own would count less, and a laid-off card can make room for the next — a 9♠ goes onto 5-6-7♠ only after the 8♠.

Laying off is never possible against gin or big gin. It is the whole reason the gin bonus is worth chasing.

If your opponent's deadwood — after laying off — is equal to or lower than yours, they have undercut you. They score the difference plus a 25-point bonus, and you score nothing for the hand you ended.

An undercut on an equal count is still an undercut: the tie goes to the player who did not knock.

Every hand is scored the same way, and only one player scores it.

A match is the first player to 100 points, or the higher score after three void hands in a row. There are no bonuses for winning individual hands beyond the ones above, and no line or box scoring — the running total is the whole score.

The stock is not played to the last card. When a player draws from it and it is left with two cards, that player may still knock; if they discard instead, the hand is over: nobody scores, the match total does not move, and the same dealer deals again, from a freshly shuffled deck.

Two cards rather than zero because the alternative is a turn with no draw to make, which is not a turn. It leaves the game with a third outcome besides winning and losing the hand, and one both players can aim at: a player protecting a match lead can simply decline to knock, and a player who needs points cannot afford to let them.

Taking the top of the discard pile never uses up the stock, so a hand could otherwise go on for ever with each player taking what the other threw. It cannot: twenty turns in a row that all took from the discard pile — ten each — void the hand the same way, at the discard. A single blind draw starts that count again.

A match ends the moment a player reaches 100 points. That player wins, and a hand cannot be won by two players at once, so there is never a tie at 100.

It also ends if three hands in a row run the stock down without anybody scoring. Nobody can stall a match for ever by declining to knock: the third void hand in a row ends it on the score as it stands, the higher score winning and level scores — including 0 to 0 — being a draw. A hand that scores, by a knock or an undercut, starts the count again from nothing.

The rule that three voids end the match is what makes a lead worth protecting. Ahead on points, you can decline to knock and run the stock down twice; behind, you cannot afford to let the third come.

Gin Rummy is two players, rated with Glicko-2, with 45 seconds on each turn. Both players hold hidden cards, so tables are not open to spectators: whether to show a watcher two face-down hands is a decision nobody has made.

It can also be played a move at a time, hours apart, for people who would rather not sit at a clock.

Play it against a bot, in the queue against another player, or a move at a time. There is also a one-hand tutorial, a five-rung ladder (four single hands, then a full game to 100) and a set of achievements.