Gin Rummy Rules and Strategy for Two

The rules

1. Deal: ten cards each. The next card is turned face up to start the discard pile; the rest is the stock.
2. Turn: take the top card of the stock or the top card of the discard pile, then discard one card face up. (In the first turn the non-dealer may take the first upcard or pass; the game handles this.)
3. Melds: a set is three or four cards of the same rank; a run is three or more consecutive cards in one suit, with ace low (A-2-3, not Q-K-A).
4. Deadwood: the cards in your hand that are not in a meld. Pictures count 10, aces 1, other cards their number.
5. Knocking: when your deadwood totals 10 or less, you may knock after drawing, discarding one card face down. Lay out your melds; the opponent lays out theirs and may lay off cards that fit on your melds (not if you went gin).
6. Scoring a knock: if your deadwood is lower, you score the difference. If the opponent's deadwood is equal or lower, they undercut you and score the difference plus 25.
7. Gin: knocking with no deadwood at all scores 25 plus all of the opponent's deadwood, and they may not lay off.
8. The stock rule: if only two cards remain in the stock and nobody has knocked, the hand is a draw and is redealt.
9. Game: first to 100 points wins.

Strategy: the first few turns

The opening of a Gin hand is about shape. Count your melds and near-melds (two cards that need one more: a pair, or two cards in sequence or with a one-card gap in the same suit). A hand with three near-melds is promising; a hand with none needs rebuilding. In the first turns:

• Discard high cards that touch nothing. A lone king is 10 points of deadwood and attracts little.
• Keep middle cards (5 to 9): they fit into more runs than aces and kings do.
• Keep two-way near-melds over one-way ones: 7 and 8 of hearts can take the 6 or the 9; a pair of sevens needs one of two sevens.

Reading the discards

Every card the robot takes from the discard pile is information: it tells you a rank and a suit the robot is collecting. Every card the robot throws is information too: it is unlikely to want that rank or the adjacent cards of that suit. Use it both ways:

• Do not discard a card next to one the robot picked up.
• When you must discard a card that may help, discard the one furthest from what the robot has shown interest in.
• A card the robot discarded is usually safe to discard yourself soon after (a "safe discard"), because the robot would have kept it if it fit.

Knock early or go for gin?

Knocking early with 8 or 9 points of deadwood often scores 10 to 20 points and ends a hand before the opponent's melds come together. Going for gin pays 25 extra but risks the hand turning against you. A simple rule: knock as soon as you can in the first eight or so turns, because the opponent probably has plenty of deadwood; later in the hand, when the opponent has had time to meld, weigh the risk of an undercut. If the robot has picked up several discards, it may be close to gin itself: knock while you still can.

Lay-offs and undercuts

When you knock, the opponent may lay off their deadwood onto your melds (a 5 of hearts onto your 6-7-8 of hearts), which reduces their count and can produce an undercut. To limit lay-offs, knock with melds that are hard to extend (sets of four, runs ending at an ace or king) or wait one turn when your melds are open at both ends. Going gin prevents all lay-offs, which is part of its value.

Common mistakes

1. Keeping high pairs too long. Two kings are 20 points of deadwood until the third arrives.
2. Discarding next to the robot's pick-ups. It is handing over the meld.
3. Refusing to knock while waiting for gin. The 25 bonus is rarely worth an undercut.
4. Taking from the discard pile for a one-card improvement. It shows your hand; take from the stock unless the card completes a meld.
5. Ignoring the stock count. With few cards left, knock with what you have before the hand is annulled.

Glossary

• Meld: a set (same rank) or a run (same suit, consecutive).
• Deadwood: cards not in melds; their total decides knocks.
• Knock: ending the hand with deadwood of 10 or less.
• Gin: knocking with no deadwood; worth 25 extra, and no lay-offs allowed.
• Lay-off: adding deadwood to the knocker's melds.
• Undercut: the defender's deadwood equals or beats the knocker's; 25 to the defender.