The Rules of Go

Page 10
Scoring of an example position

Note:
On this page I will demonstrate the scoring using the teritorry method.
You can find an example of area scoring method applied to the same position here.
You can find both methods explained and compared here.

The scoring of the game of Go is the process by which the winner of the game is determined. There are many different methods of scoring. The one we will apply here is the one which is most popular - it is based on the subtraction of the stones you lost from the points of teritorry you made - and the resulting number is your score, which is then compared to the score of your opponent to find out who won.

The example position which we will score is given in Endgame Position of Fig 1. It is the final position of the sample game which can be found here. As you can see during the game White captured and killed one black stone. Black, for his part, captured one white stone which is still on the board - the stone marked with a triangle.

Endgame Position	Step 1
White killed: 1 stones Black killed: 0 stones	White killed: 1 stones Black killed: 1 stones

Fig 1. Scoring of an example position

The first step in scoring process is to determine which stones are dead and take them off the board as prisoners. In the above position there is only one such stone - the white stone marked with a triangle in Endgame Position. This stone is taken off the board and counts as Black's prisoner. You can see this reflected in the change from "Black killed: 0 stones" to "Black killed: 1 stones" underneath Endgame Position and Step 1 of Fig 1.

Now that we have take care of taking off dead stones from the board, we place these stones inside the opponent teritorries - so black prisoners (the stones killed by White) we fill into black areas, and white prisoners (the stones killed by Black) we fill into white areas. This can be seen in Step 2 of Fig 2 - both the stones marked with triangles (one black and one white) are placed inside respective teritorries. This results in functionally subtracting the lost stones from the gained points for both players - since by using the lost stones to fill out the areas of points which you gained - and thus diminishing the number of your gained points by the number you have lost.

Step 2	Step 3

Fig 2. Scoring of an example position (continued)

The last step in the scoring process is to count the number of remaining points inside of each players teritorry. These points will then be compared and who of the players have more is the winner.

Looking at Step 3 of Fig 2 we can see the points inside black teritorry marked with 'b' (for Black) and the points inside white teritorry marked with 'w' (for White). Counting these points gives us 17 for Black and 17 for White - so the score is even on the board! So the winner of the game depends on the value of komi (more about it here) - and in the absence of komi a equal game is usually awarded to White (so we can say that there is a customary 0.5 point komi for White in no-komi games). Assuming this was a regular game between players of equal strength, the komi would be 5.5 points for White - and this would also be the number of points by which White wins this game.

In short - White wins by 5.5

Note:
Notice that the point marked 'a' has not been counted for neither side. Such points are called dame - they are between black and white stones and unclaimed by neither player. However, there are scoring methods (the area scoring for example which, together with other scoring methods, is explained Jasiek's Go Homepage) which do count dame points in one way or another. This is, however, a topic which transcendes the purpose of these pages. Please follw the above hyperlink to learn more about various rule-sets and scoring methods.