OGS - Rules and Scoring FAQ

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"Japanese" and "Chinese" Scoring Systems

There are two main methods of scoring in Go, Territory scoring rulesets such as J1989 (Japanese) and area scoring rulesets such as Ing (Chinese). Whilst quite different in their method, in an average game the outcome will be virtually identical in almost all cases (the main exception being where one player has wasted a number of moves placing intersections in their own territory - in this case, territory scoring rulesets are less forgiving). On the whole, the territory scoring systems seem to be more widely used on most internet servers, although for a beginner I believe it can be quite unforgiving as it penalises moving in your own territory - a beginner can often have trouble knowing when a move is necessary for positional strength, or when it is simply throwing points away.

OGS does not use a direct implementation of any of the existing rulesets, as many of the parts of the rulesets can get extremely complicated. Instead, OGS uses a simplified and easy to understand couple of rulesets, a territory one referred to from now on as "Japanese" and an area one referred to from now on as "Chinese".

The other main point of contention in scoring is what is known as "Komi". This is the "free" points awarded to white to balance the fact that black moves first. This number is steadily rising, but tends to be 6.5 or 7.5 depending on which ruleset you play to. Because of the variation in Komi, each game on this site can be set with a Komi value ranging from -30 to +30, and each player can set their own default Komi value for starting games in their profile. An "even" game on this server is currently always 6.5 komi.

There is currently a proposal to move (as the default even value) to 5.5 komi for 9x9 boards, 7.5 komi for 13x13 boards and 6.5 komi for 19x19 boards for Japanese rules, and 1 more than this for Chinese rules. At the moment, nothing has been done with the proposal whilst discussions continue.

Scoring in detail

Points in go can be awarded as follows:

• Komi - If you are white, you receive a free number of points to compensate for the disadvantage of moving second (the actualy number is whatever the Komi value has been set for that board).
• Stones on the board - In Chinese scoring, you are awarded 1 point for each stone you have on the board at the end of the game. In Japanese scoring, stones are disregarded beyond their use for setting territory zones.
• Opposing stones captured - In Chinese scoring, captured stones are ignored. In Japanese scoring, you lose a point for each of your stones that were captured by your opponent in the course of the game. These are displayed to the left side of the board below the word "prisoners".
• Territory owned - The complicated part of the scoring system for beginners. Owned territory is empty squares (either individual squares or a group connected horizontally and vertically) surrounded by stones of only your colour. In both scoring systems you gain 1 point for each square of territory owned. Examples of owned and contested territory are shown below:

In this example black owns the three squares in the middle of his stones, as they are surrounded either by his stones or the edge of the board.

In this example black owns the two squares in the bottom right, and the two surrounded holes just above.

In this example white owns the two squares in the middle of his stones, and the single hole in the bottom left also surrounded by either his stones or the edge of the board.

In this example both of the empty areas are contested, as both are surrounded by at least one of each colour stone

If you resign or timeout your score will instantly be set at 0.

Dead Stones:
If a stone or group of stones are clearly dead, and both players are aware of this, the game will normally finish by agreement with the stones left on the board. In this case, the stones are then marked as dead and treated for scoring purposes as if they have been captured.

The following is an example board to demonstrate how the scoring works in practice:

In this example, black has 23 stones and has captured 2 of white's stones, and white has 23 stones and has captured 1 of black's stones. The territory on squares f3 and g4 are contested and therefore not worth points to either side. Black owns 17 squares of territory and white owns 16 squares of territory.

In Japanese rules, white's total score would be:
16 (territory) - 2 (captured stones) + 6 (komi) = 20

and black's total score would be:
17 (territory) - 1 (captured stones) = 16

In Chinese rules, white's total score would be:
23 (stones) + 16 (territory) + 6 (komi) = 45

and black's total score would be:
23 (stones) + 17 (territory) = 40

Therefore white would be the winner in this position in either scoring systems, the difference being 4 points with the Japanese rules and 5 points with the Chinese rules.

Eyes in Seki

The only other difference between scoring rules is regarding the scoring of stones and groups in seki. Some sekis contain false eyes that cannot be removed - this count as points in Chinese rules but not in Japanese rules. At the moment OGS is not capable of having these false eyes recognised, and as such awards them as points even in games with Japanese rules. If this happens in one of your games please raise a support ticket and we will get the game resolved.

Resumption

In both rulesets, should the two players not manage to agree on dead stones, the first player to pass resumes play with the next move on the board. One move has to be made by each player before passes are again permitted.

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