Oklahoma Gin is played with a 52 deck of cards, no jokers. Hands consist of 10 cards for 2 players and 7 cards each for 3-6 players. The remaining cards are placed face down as the stock pile and one card is placed face-up on the table to start the discard pile, this is the opening card (i.e. 8). The cards’ numbers represent their scores with the jack queen and king all scoring 10.
The object of the game is to create melds of runs or sets within your hand, and then reduce the value of any ‘deadwood’ cards to less than that of your opponents. You do this by taking a card either from the stock pile or the discard pile and then disposing of a card. You must dispose of a card to complete your turn. Any cards not included in a meld are referred to as deadwood.
In Okalahoma Gin there are 3 ways of winning the game and therefore scoring the points of your hand; ginning, knocking and undercutting.
The player who ‘gins’ has no ‘deadwood’ or unmatched card and disposes of all his cards as sets or runs. If you have some deadwood but its value is lower than the opening card (i.e. 
then you can ‘knock’. When a player ‘knocks’ this give his opponents a chance to layoff their deadwood onto the knockers melds. So you could put a 5 of hearts on the knockers run of 2, 3 & 4 hearts, thus reducing your deadwood score. You can only lay-off deadwood on the knockers’ melds and not on a ‘gin’ hand.
After you have laid off, if your deadwood score is lower than the knockers deadwood score then you have ‘undercut’ them and they lose the round, receiving 10 extra penalty points.
Penalty points are awarded to the losing players. If you lost to a Gin hand, the sum of the games deadwood plus 25 penalty points. For losers to a Knock, it is the sum of the games deadwood minus the knockers’ deadwoods, and for those who were Undercut it is the sum of the games deadwood minus the undercutter’s deadwood plus the Knocker receives an extra 10 penalty points.
The winner of the tournament is the last player who has not exceeded the penalty point elimination level, or the first player to accumulate the required score.