Chinese vs Japanese Rules in Go: What Actually Differs
Chinese and Japanese rules produce the same game almost all of the time. The stones move the same way, capture the same way, and the winner is the same player in the overwhelming majority of games. What differs is how the final position is counted, how much komi White gets, how repetition is handled, and what happens when the two players disagree about a group. This site uses Chinese rules: area scoring, 7.5 komi, positional superko.
The moves are identical
Every rule you learn from the rules of Go applies under both systems. Stones go on intersections, groups die when their last liberty is filled, suicide is illegal, you cannot immediately recapture in a ko. If you learned Go on a Japanese-rules board you already know how to play on a Chinese-rules one, and you would never notice the switch until the game ended.
That is the part worth holding on to. The differences below are real, but they are differences of accounting.
Scoring: area or territory
Chinese rules use area scoring. Your score is your stones on the board plus the empty points you surround. Japanese rules use territory scoring. Your score is the empty points you surround plus the stones you captured during the game, and your own stones on the board count for nothing.
Count it as Chinese rules do. Black has 8 stones and 19 surrounded points, so 27. White has 7 stones and 14 surrounded points, so 21. Black leads by 6.
Now count it the Japanese way. Black has 19 points of territory, White has 14, and neither player captured anything all game. Black leads by 5.
The gap is one point, and the reason is visible in the stone counts: Black has 8 stones on the board, White has 7. Black moved first, so Black placed one more stone. Area scoring counts that stone, territory scoring does not. As long as both players have laid the same number of stones, the two methods give an identical margin. When Black has one extra, area scoring reads one point better for Black. That is the whole of it, and it is why the two systems almost never disagree about the winner.
Komi: 7.5 or 6.5
Chinese rules use 7.5 points of komi. Modern Japanese-rules events use 6.5, as do Korean ones, which use a territory-based count of their own. The difference is exactly the one point explained above: area scoring hands Black a point that territory scoring does not, so area scoring charges Black a point more for it.
Treat 7.5 and 6.5 as the same balance expressed twice rather than as two different opinions about the value of the first move. Komi covers where the number came from.
Ko and repetition
Both systems ban the basic ko, the one-stone-for-one-stone loop that would otherwise never end.
Chinese rules go further with positional superko: no move may recreate any whole-board position that has occurred before. One sentence, no exceptions, and it disposes of every long repetition (triple ko, eternal life, and the other exotic loops) with the same rule that handles the simple case.
Japanese rules ban the immediate repeat and then handle the rare long cycles with separate provisions, which in some cases end the game as a no-result to be replayed. This is one of several places where the Japanese rule text has to be long and careful where the Chinese one can be short. The ko rule page covers what this means in an actual fight, which is the same either way.
Suicide
Illegal under both. You may not play a stone that would leave its own group with no liberties, unless that same move captures an enemy group first and frees a liberty. New Zealand rules are the best-known set that allows suicide outright, and a handful of others permit it in limited forms, but neither of the two main systems does.
Ending the game, dame, and disputes
Both systems end the game on two consecutive passes. What happens on the way there is not quite the same.
Under area scoring, the neutral points called dame are worth a point each, because a stone placed on one still counts as a stone. So players fill them all before passing. Under territory scoring dame are worth nothing to either side, so they get filled as a formality or skipped. How a Go game ends works through both.
Disputes over dead stones diverge further. Chinese rules resume play: if you think a group is dead, prove it on the board, and whatever happens is the answer. Japanese rules settle it with a separate hypothetical analysis, under its own set of conventions, because resuming play would disturb the territory count. Chinese rules can afford to resume precisely because extra stones cost their owner nothing.
Handicap placement
Japanese rules fix where handicap stones go. Four stones means the four corner star points, every time.
Chinese rules let Black put the same stones anywhere. Most players still choose the star points, but nothing stops Black from stacking them down one side, or taking the 3-3 points instead.
Handicap komi also differs slightly between rule sets, and handicap Go covers the usual 0.5.
AGA rules, the hybrid
The American Go Association uses area scoring with 7.5 komi, plus one addition: pass stones. A player who passes hands the opponent a captured stone, and White must make the last pass. The effect is that counting the board as territory and counting it as area give the same number, so a player trained on either system can count an AGA game their own way and get the right answer.
It is a neat piece of engineering, and it is the clearest evidence that the gap between the two main systems is narrow enough to bridge with a single extra convention.
Why this site uses Chinese rules
Three reasons, all practical.
Area scoring is unambiguous for a computer. Every point on the board belongs to Black, to White, or to neither, and that can be worked out from the position alone with no reference to what the players intended.
Extra stones cost nothing, so there is no way to hurt yourself by playing on. A beginner who is not sure whether a group is alive can just keep playing until it obviously is, without paying for the certainty. Under territory scoring those moves cost a point each, which is a nasty thing to spring on someone who is still learning.
Positional superko is easy to enforce exactly. The engine already has every previous position, so checking for a repeat is a lookup, and a rule that is enforced exactly cannot be argued about.
Which should you learn first
It does not matter. Learn one, play a few hundred games, and pick up the other in ten minutes when you first need it. Nobody has ever lost a game because they trained on the wrong ruleset, and the strategy, the shapes, and the reading are all identical.
If you want the version this site plays, that is area scoring with 7.5 komi. Start a game and it is applied for you.
Frequently asked questions
Which rules are used in professional Go?
It depends on where the tournament is. Japanese titles use Japanese rules, Chinese events use Chinese rules, Korean events use a territory-based system close to the Japanese one, and international events adopt whichever the host organisation runs on. Top players simply play under whichever set is in force that week.
Do I need to learn both?
No. Learn the one you are playing under and read the other when you meet it. The only things you actually have to adjust are whether your own stones count and whether filling a dame is worth doing.
Is 7.5 komi Chinese or Japanese?
Chinese. 7.5 goes with area scoring, which is what this site and most online servers use. Japanese rules pair territory scoring with 6.5. Both settings describe the same balance between Black and White.