Gin Rummy is a two-player game which rose in popularity early in the 20th century, and then again in the 1940s until it was finally eclipsed by Canasta.
Standard deck of 52 cards.
Each player is dealt 10 cards one at a time. Place the rest of the deck, face down in the middle of the table to form the stock. Take the top card, and place it face up to start the discard.
Throughout play, the discard pile is kept squared up.
Melds are collected, but are not revealed until one player ends the hand by knocking whenever his unmeldable cards total 10 or less, counting Ace equals 1, and any Court Card equals 10.
The Knocker then wins and scores unless his opponent ties or undercuts him, in which case the opponent wins a bonus.
To start, the non-dealer must either take the upcard or pass. If he passes, the dealer must then either take the upcard or pass. If he passes too, the non-dealer begins by drawing from the stock.
Thereafter, each in turn draws from the stock or takes the upcard, then plays a card face up to the discard pile.
If the upcard is taken, the discard must be different.
Either player, upon drawing a card, may end the game by knocking, provided the he can meld enough cards in his own hand, and their deadwood, (i.e. unmelded cards) does not exceed the value of 10.
The player signifies this by discarding face down, and then laying their hand out face up, arranged clearly in the melds and deadwood of which it consists.
The opponent, then, similarly lays their hand out, face up, arranged into the melds and deadwood that he/she has, laying off to the knocker’s melds as he/she chooses, and reveals his/her own deadwood.
If the knocker went Gin, his opponent may not lay off cards against the knocker’s melds.
If the Knockers deadwood is less than his opponent’s, he scores the difference between the two totals.
If he melds, all his cards “goes gin”, having no deadwood, he adds a bonus of 25.
Only the knocker can “go gin”. Even if the opponent can reduce his score to zero, the knocker still scores his bonus 25.
If the opponent has an equal or lower count of deadwood, he not only scores the difference, and also adds a bonus of 25 for undercut.