0913-card rummy rules, sequence by sequence

The deck and the deal

A standard 13-card rummy game uses one or two standard 52-card decks, plus printed jokers. In a one-deck game, there is one printed joker; in a two-deck game, there are two. The decks are shuffled together, and 13 cards are dealt to each player, face down. Two cards are placed face down in the closed deck, and one card is turned face up to start the open deck.

The face-up card is the open joker for the hand, with one exception: if the face-up card is itself a printed joker, the next card is turned up and becomes the open joker. This rule is sometimes called the "printed joker exemption".

The draw and the discard

On each turn, the active player draws one card, either from the top of the closed deck (face down) or from the top of the open deck (face up). The player then discards one card from their hand, face up, to the open deck. A turn is complete when the discard is made.

The order of play is clockwise, starting with the player to the dealer's left. A player who is not active may not draw or discard.

Sequences and sets

A sequence is three or more cards in the same suit, in consecutive order. A pure sequence contains no jokers. An impure sequence contains at least one joker, which substitutes for a missing card. The Ace can be high (Q-K-A) or low (A-2-3), but cannot wrap around (K-A-2 is not a valid sequence).

A set is three or four cards of the same face value, in different suits. In a one-deck game, a set can have at most one card from each suit. In a two-deck game, a set can have two cards of the same suit (using both decks).

The declaration

A valid declaration needs three groupings: one pure sequence, one second sequence (pure or impure), and a third grouping (sequence, set, or both). All 13 cards must be grouped; any ungrouped card at declaration is an invalid show.

You declare by laying your 13 cards face up on the table and discarding your final card to the finish slot. Other players may then challenge any grouping; an invalid grouping on challenge means the declarer pays the maximum score, not zero.

The scoring

At the end of the hand, every losing player ungrouped cards are summed. Numbered cards carry their face value, face cards (J, Q, K) carry 10, the Ace carries 10, and the printed jokers carry 0. A player with a valid declaration scores zero. A first drop usually costs 2 points on a points table; a middle drop usually costs half the entry. A full-count loss is the face value, capped at 80 on most platforms.

The drop, in detail

The drop is a tool, not a failure. A first drop is allowed before the player has drawn a second card. A middle drop is allowed at any point after the first draw, up to the last turn before the declaration. The drop values are platform-specific; read the table rules before you sit down.

The challenge, in detail

A challenge is a formal objection to a specific grouping. The challenger names the grouping (for example, "I challenge the second sequence") and the platform's rules engine (or, in a home game, the other players) verify the grouping. An invalid grouping on challenge means the declarer pays the maximum score; a valid grouping on challenge means the challenger pays a small penalty (usually 2 points).

Common house variations

Most platforms play the rules above without modification. A few allow the printed joker to substitute for the open joker in a pure sequence (this is a house rule, not the standard). Some platforms cap the full-count loss at 80 in 13-card points and at 80 in 101-pool, and at 80 in 201-pool. Read the table rules before you sit down; the variations are small but real.

A worked hand, step by step

Take a hand of 13 cards as an example. The hand has hearts 4-5-6, spades 7-8-9, the printed joker, a 7 of clubs, a 7 of diamonds, a Queen of hearts, and a King of spades. The first priority is the pure sequence: hearts 4-5-6 is a pure sequence, and the pure sequence is locked in. The second priority is the second sequence: spades 7-8-9 with the printed joker replacing the 7 of spades is an impure sequence, and the impure sequence is locked in. The third priority is the set: 7-7-7 of clubs, diamonds, and hearts is a set, and the set is locked in. The remaining cards are the Queen of hearts, the King of spades, and they are the ungrouped cards.

The full-count at declaration would be 20 (10 for the Queen, 10 for the King). The reader can either declare with a full-count of 20, or replace the Queen with a discarded 10 of hearts to make a fourth grouping and declare with a full-count of 0. The math favours the second move: dropping the full-count from 20 to 0 saves 20 points at a 1-rupee table and 40 points at a 2-rupee table.

When the math does not favour the cleaner hand

Sometimes the cleaner hand is not the hand the cards will support. A hand with two competing pure sequences in two suits and no set will spend three turns sorting, and the reader will burn the third turn sorting instead of pulling the cards the hand needs. The math of the sort is not free, and the math of the sort is the part of the priority the reader should plan for.

The test is whether the hand can lock a pure sequence in the first five turns. If the answer is no, the hand is a drop hand, and the reader who drops the drop hand is the reader who has read the sequence priority correctly.

The four invalid-show conditions

A show is invalid when one of four conditions is true. The first condition is a missing pure sequence: the hand does not have a pure sequence, and the reader has declared. The second condition is a missing second grouping: the hand has a pure sequence but no second sequence or set, and the reader has declared. The third condition is an ungrouped card: the hand has all three groupings but one card is not grouped, and the reader has declared.

The fourth condition is a wrong grouping: the hand has three groupings but one of the groupings is not valid (a sequence that wraps, a set with a joker in a pure sequence, an Ace used both high and low). A wrong grouping is the invalid-show condition most new readers miss, and a wrong grouping is the invalid-show condition that costs the most points.

What happens after an invalid show

An invalid show is treated as a full-count loss with a multiplier. Most platforms apply a 2x multiplier to the full-count, and the multiplier is applied to the ungrouped cards. A reader with a full-count of 67 on an invalid show pays 134 points. The multiplier exists to discourage careless declarations.

The reader who treats the invalid-show rule as a checklist is the reader who does not pay the multiplier. The checklist is: pure sequence present, second grouping present, third grouping present, all 13 cards grouped, no Ace wrap, no joker in a pure sequence, no duplicate card. The reader who runs the checklist before declaring is the reader who has done the cheapest safety check the format offers.