The objective of Gin Rummy is to form sets (groups of cards of the same rank) and runs (consecutive cards of the same suit) in your hand. Minimize unmatched cards and achieve a lower total deadwood count than your opponent.
Each player starts with 10 cards, and 1 card is turned face up as the discard. Players take turns drawing a card from the deck or discard, aiming to make sets and runs in their hand. Players can knock if they have few unmatched cards, and after knocking, both players reveal their hands to see who has fewer unmatched cards and scores points.
To knock, a player discards a card face-down and declares that they are knocking. The other player then has a final turn to lay down their sets and reduce the value of their unmatched cards.
After knocking, both players reveal their hands. Unmatched cards in the knocking player's hand are counted. If the knocking player's unmatched cards have a lower total point value than the other player's unmatched cards, the knocking player wins the hand and scores points based on the difference.