In Go, Black always plays first. Having the first move is a real advantage: Black gets to claim the first corner, set the pace of the opening and, in a game between equal players, usually finish ahead if nothing else changes. To make the game fair, White receives komi, a number of extra points added to White's score at the end.
This article explains why komi exists, why this site uses 7.5 points, what the half point is for, and how komi should affect the way you play.
The first-move advantage
In the opening, every move claims part of the board. Black, moving first, is always one move ahead. That extra move is worth something, and experience from many games between players of equal strength shows that Black tends to win more often when no compensation is given.
Komi is that compensation. It is not a gift to White and not a penalty for Black; it simply balances the one-move head start so that the better player, not the player who moved first, wins.
Why 7.5 on this site
This site uses area scoring, where you count your stones on the board plus the empty points you surround. Under area scoring, a komi of 7.5 points is the value most commonly used. Under territory scoring, the value commonly used is 6.5 points. The two numbers differ by one point because the two counting methods differ slightly in how the last neutral points and the parity of the board work out; in practice both give very similar results between equal players.
Komi values have increased over the history of the game as players and analysis found that a smaller compensation still left Black ahead. The exact numbers chosen by different organisations still vary, so if you play elsewhere, check which komi is used.
Why the half point
Komi almost always includes a half point. Because every stone and every point on the board is a whole number, adding half a point makes a tie impossible. One side always wins by at least half a point. Games decided by 0.5 points are real and happen regularly in close games; they are one reason endgame accuracy matters so much.
Komi and small boards
On small boards, the first-move advantage can be larger relative to the board. On a 9×9 board, a strong Black player can often build a winning position quickly. Some organisations use different komi values for small boards. On this site, komi is 7.5 on every board size, which keeps things simple and consistent between 9×9, 13×13 and 19×19.
How komi affects strategy
Komi changes how each side should think:
- Black knows that simply staying even is not enough. Black must actually get ahead by more than 7.5 points on the board. That encourages Black to play actively and make the most of the first move.
- White knows that an even-looking position is actually a White lead. That allows White to play more calmly, avoid unnecessary risks and aim for a close game.
When you estimate the score during a game, always add komi to White's side before deciding whether you are ahead. A position where Black has five more points on the board is actually a White lead of 2.5.
Komi and handicap games
When players of different strength meet, the weaker player can be given handicap stones: extra black stones placed on the board before the game starts. In handicap games, komi is usually reduced or removed, because the handicap stones already compensate for the difference in strength. Typical practice is a small komi, often half a point, so that ties are still avoided.
This site's online games and computer games are even games with komi 7.5.
Common misunderstandings
"Komi means White is weaker." No. It only means White moved second.
"I won by 3 points on the board, why did I lose?" Because you were Black and forgot komi. On the board you were 3 points ahead; after 7.5 komi, White won by 4.5.
"Komi is too big, Black can never win." Between equal players, Black and White win roughly equally often with the right komi. Black wins by playing well enough to overcome it, which happens all the time.
Counting with komi in mind
A simple habit: at several points in the game, do a rough count of both sides' areas and add 7.5 to White. If you are Black and behind by a little, you need to take some risks. If you are White and even on the board, you are already ahead and can play safely.
The article on counting during the game gives a quick method, and area scoring explained covers the final count.
Komi and passing
At the end of a game on this site, both players pass in a row and the board is counted, with komi added for White. Remember that dead stones must be captured before passing, because the count uses the stones on the board. A careless pass with a dead stone inside your area can easily cost more than the half point that decides close games.
How komi feels in practice
For new players, komi often feels abstract until the first game decided by it. You finish a game believing you won, count the board, and discover that White is ahead by 1.5 points. After that game, most players never forget komi again. It is worth making that lesson cheaper by counting with komi from the start.
Play a few 9×9 games against the computer on the home page as Black and as White, and count each result carefully, including komi. You will quickly get a feel for how big 7.5 points is on a small board: it is roughly the size of a small corner. On 19×19, the same 7.5 points feel much smaller relative to the board, which is why endgame accuracy and small edges become so important there.
Practice
Try playing both colours against the computer on the home page and compare how your strategy changes. As Black, look for ways to use the first move actively. As White, practise keeping the game calm and close. Against people on the online page, notice how often games are decided by a few points. If you sign in on the account page, you can replay close games and see exactly where the half point was won or lost.
Frequently asked questions
What is komi?
Extra points given to White at the end of a Go game to compensate for Black moving first.
How much is komi on this site?
7.5 points, on every board size.
Why is there half a point?
To make ties impossible. One player always wins by at least half a point.
Why do some places use 6.5 instead?
That is the value commonly used with territory scoring. With area scoring, 7.5 is common. The two systems give very similar results.
Is there komi in handicap games?
Usually only a small komi or none, because the handicap stones already balance the difference in strength.
