Knocking: A player may knock, after having drawn a card, when the total point value of cards not incorporated into melds (i.e. the unmatched cards) is no more than the value of the knock card. The intended discard is not counted. The knocking player places his cards face up on the table arranged into melds and unmatched cards. The opponent also places his cards face up and tries to layoff all the unmatched cards against the knocker's melds. The hand is now over and counting begins.
A player who is able to knock does not have to knock. He may instead choose to continue playing and try for gin or a lower total point count.
Scoring: After knocking, each player counts the total point value of his or her unmatched cards. If the knocker's count is lower, the knocker earns the difference between the counts. If the opponent's count is the same or lower, the knocker is undercut, and the opponent earns the difference between the counts. Knocking with no unmatched cards is called gin (and earns a bonus.)
Ending: The game ends as a player reaches the agreed upon number of points.