The purpose of Gin is of course to win each individual hand, but the ultimate goal is to win the entire game. You do this through the individual hand scores which will lead you to the final game score.
The point total for a head to head or two-handed game is 250 points. That can vary depending on whether you are just playing for fun with family or friends, but for competitive gin rummy, the game will always be to 250 points. The way you get to your total is by getting the maximum amount of points you can in each individual hand to give you the final, and hopefully winning score. You score points by knocking before your opponent does, but there are also bonus points that can be added during each individual hand. This includes going gin, or underknocking an opponent. The scoring for the winner of the individual hand is simple but it does take some knowledge of how to do it.
When a player knocks, he puts down his melded cards which have no value in figuring the total point count of his hand. The player totals only the unmelded or unmatched cards to get a total count. For example, if a player melds with three Kings and three 10’s and is left with a four, a three, and two aces, they are left with 9 points. If the knock card is a nine or higher then they could knock with 9 points to possibly win the hand. If the opponent has only one meld of queens in his hand and is unable to lay off any unmelded cards, leaving him with total of 7 unmelded cards adding up to 32 points, then the person who knocked will get the difference between his 9 points and the opponents 32 points. That would mean that the knocker would receive 23 points. Another example would be if the knocker was left with 3 points, and his opponent has 16 points then the difference of 13 points would be awarded to the person who knocked. Each hand is done exactly this way, unless there is gin or an underknock.
If the winning player has gotten gin he would receive the point count of the unmelded cards in his opponent’s hand plus the established bonus for gin. In an underknock, which is when the opponent ended up with less points then the person who actually knocked, the person who claims the underknock will receive the difference in points plus the appropriate bonus as well. If his count was exactly the same, meaning they tied in point count leading him to get an underknock, he would only receive the bonus amount. The only variation of the scoring occurs in more modern games when the score is doubled based on the suit of the knock card. In this case, if the knock card is a spade or heart the entire score will be doubled.