Go (Baduk) Score Counting Calculator

Understanding the Go (baduk) score counting calculator — concept and principle

At the end of a game of Go (baduk in Korean, weiqi in Chinese), the winner is decided by counting points. Two main methods are used: territory scoring, used under Japanese and Korean rules, and area scoring, used under Chinese rules. This calculator applies both to your counts, adds komi for White, and shows who wins and by how much.

How it is calculated

• Territory scoring (Japanese/Korean): Black = territory + prisoners; White = territory + prisoners + komi. Prisoners include stones captured during the game and dead stones removed at the end.
• Area scoring (Chinese): Black = territory + Black stones on the board; White = territory + White stones + area komi. Prisoners are not counted. The area komi is a separate input, 7.5 by default as under Chinese rules.
• The margin is the absolute difference between the two totals.

The principle

Both methods measure the same thing: how much of the board each side controls. Under area scoring a stone on the board and an empty point you surround are each worth one point. Under territory scoring only empty points count, but every stone you capture costs your opponent one point. If both players have made the same number of moves, the two methods give the same margin, apart from at most one point from who played last, dame and seki. Komi compensates White for Black's first-move advantage; the half point prevents ties.

Worked example

1. Inputs: Black territory 60, Black prisoners 10, White territory 55, White prisoners 8, komi 6.5.
2. Territory scoring: Black 60 + 10 = 70; White 55 + 8 + 6.5 = 69.5, so Black by 0.5 (70 – 69.5).
3. Area scoring: Black 60 + 120 = 180; White 55 + 118 + 7.5 = 180.5, so White by 0.5 (180 – 180.5).
4. Before komi, Black leads by 7 under both methods (70 − 63 and 180 − 173). The result flips only because Chinese komi is one point larger.

How to read the result

Most professional games are decided by a few points, so a 0.5-point margin is a real win, not a draw. If the two scoring lines disagree, as in the example, check the komi first. Under area scoring on a 19 × 19 board, all points are counted once the neutral points (dame) are filled, so the two totals before komi should add up to 361; a big gap means a miscount.

Common mistakes

• Adding prisoners under area scoring; they are already reflected in the stone count.
• Forgetting the dead stones removed at the end of a territory-scored game.
• Mixing komi values: 6.5 is used under Japanese and Korean rules, 7.5 under Chinese rules.

Frequently asked questions

Why is komi a half point?

With a fractional komi the totals can never be equal, so every game has a winner.

Does the method change who wins?

Rarely. With the same komi the margin usually differs by at most one point; different komi values cause most disagreements.

What are prisoners?

Opponent stones you captured during play plus dead stones removed after both players pass.

Sources: Nihon Ki-in and Kansai Ki-in, Japanese Rules of Go (1989) · Chinese Weiqi Association, Chinese Rules of Weiqi