If a player has 10 points or less in deadwood, they are allowed to knock. Both players reveal their hands after the knock, and any cards that don't match are deducted from their teen patiscore according to their face value (face cards are worth ten points). The knocker scores points according to the difference between their opponent's deadwood and their own; if the opponent's deadwood is equal or less, they win with an "undercut," earning bonus points. The combination of offensive and defensive play in Gin Rummy gives it strategic depth.