The winning score for Gin can be determined by the two players involved in the game or the game can be played until one player reaches a score of 100 or more points. If you are playing an online or computer software version of Gin, the winning score will be predetermined. Aside from the winning score, the point values throughout the game of Gin are fairly standard and are described below.
In Gin the Ace is a low card, meaning that it counts as a 1, preceding the 2 and 3 of its suit, rather than acting as a high card that succeeds the Queen and King. All Aces in Gin are worth 1 point. Face cards, which refer to the Jack, Queen and King of each suit, are all worth 10 points each. The remaining cards, 2-10, are worth the value of their rank. So, the 2 is worth 2 points, and the 10 is worth 10 points.
Beyond this, there are a couple of other scoring considerations for Gin. The strategy of knocking is a key part of the winning strategy in Gin. When a player knocks his opponent, both players must lay their cards on the table, revealing their sets, runs and remaining cards should they have them. The knocker's remaining cards must equal no more than 10 points, and the opponent can add to these points by creating sets or runs with their remaining cards and the knocker's remaining cards.
If the knocker's opponent is unable to do the latter, the knocker will get the difference between his opponents remaining cards and his remaining cards. For example, if the knocker's remaining cards total 5 points (perhaps an Ace of Queens and a 4 of Clubs), and the opponent's remaining cards total 11 points, the knocker will get an additional 6 points added to his score.
Another possibility is that the knocker's opponent has remaining cards that total the value of the knocker's remaining cards or is less that the value of the knocker's remaining cards. For example, the knocker's remaining cards equal 7 and the opponent's remaining cards equal 7 or the opponent's remaining cards equal 5. If this happens the knocker has been undercut, and the opponent will receive the difference, if any, between the knocker's remaining cards and his remaining cards as well as a 10 to 25 point bonus.
If the knocker has no remaining cards the game is automatically won; this is called "going gin." If the knocker goes gin he will receive a 20 to 25 point bonus as well as the value of the opponent's remaining cards. In addition, there is a 100 point bonus for whichever player reaches the game's winning score first. An additional 100 points can be won by the game's first player to reach the winning score if his opponent has managed to score no points at all. A final scoring possibility in Gin is the "line bonus." This refers to the additional 20 points a player receives per hand he has won.