Gin Rummy

In the game of Gin Rummy the most overlooked factor in the game is most definetly the under knock, however it is as important as the knock itself.  When you opponent knocks, the card values are counted and at which time the person that has knocked puts a value on any unmatched cards still in their hand.  At this point, the players that have not knocked with then start to value their unmatched cards as well.  You can also lay off your unmatched cards to any melds.  If after you have melded and lay off any cards that were originally unmatched and your total is less then the person that knocked you have under knocked and are considered the winner of the hand.   

Many Gin players can say that this can be confusing, but once you learn the finer points, it is one of the easiest things to calculate.  I will give an example that can help someone new to under knocking understand the finer points.  Your opponent has just knocked and has five points remaining in unmelded cards.  You would turn over your hand and show that you have four unmatched cards; however, you notice that three of your cards can be added to the melds that the person that knocked had.  When you can lay off cards, this simply means that you are able to continue a meld that the knocker had, such as continuing a run or adding a card to a three of a kind, if you are able to lay off these cards and your total of unmatched cards after this is equal to or lower than five, than you have successfully under knocked.  If you are able to lay off all your cards you have accomplished what is called a gin off, which is similar to an under knock, except you have reduced your points to zero and would be awarded bonus points.