Is there a reference for go rules in OGS documentation?

The day a triple ko happens on OGS, it will surely be an enjoyment for an admin to supervise it.

This page lists 26 examples of triple ko in pro play up to 2018. Of those, about ten appear to have been Japanese.

On another page, the site says that there were 168,813 Nihon Ki-in games played by 2007. Let us suppose that number rose to 200,000 by 2018. That provides a frequency of 10 / 200,000 = 1 / 20,000.

OGS is just about to hit 36,000,000 games. Suppose that 10% of games have been 19x19, and that 10% of those games have had players skilful enough to make a triple ko. 36,000,000 / 100 = 360,000.

360,000 / 20,000 = 18 triple ko games. Perhaps my skill margin is too large and should be closer to 5%, with a resultant estimate of about 10 games.

A squaring range of 5 – 25 triple ko games is probably accurate… (of if not, then the cubing range of 3 – 27).


If some of you are enthusiastic about writing up the rules reference, why not start it on the OGS wiki?


Nice stat try.
36 000 000 is quite an amount. Were all those games really games or shall we alrrady put some more aside?

Maybe thr first step would be to have the original rules well followed by OGS system.


Well, I checked 10 random five-digit game ID’s, and they were all “really games”.
This is getting a bit off-topic though.

That’s not something any of us has the power to do, though. At least we can document the status quo.

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Who wants to just write some rules now? I’ll make this page a wiki so everyone can add to it. If it starts looking good, I can copy it to the OGS wiki on github. If we can document the OGS version of Japanese rules we can probably document any of them, right?

OGS Japanese Rules

This page describes the specifics of the Japanese rules as implemented on OGS. You can find many more details at Japanese Rules at Sensei’s Library, but note that on OGS there are some differences.

Starting the game

Komi is 6.5 by default; handicap stones, if any, are placed automatically at fixed positions, namely the “star” points in the configurations you can see here Handicap Placement at Sensei's Library, depending on the number of stones.


Starting with Black, players place stones or pass alternately. Suicide is forbidden. There is no rule forbidding repetition of earlier positions of the board, except the usual ko rule Ko at Sensei's Library.



During scoring, if either player requests a resumption of the game, the opponent of the last player to pass plays the next move. That is, the game continues from where it stopped. This differs from the traditional Japanese rules.

Click edit now and contribute something to these rules!


I’m not sure there’s need to mention the default komi, since, if I understand correctly the actual rules don’t specify that. On the other hand the rules to which sensei’s library links seem to specify a 19x19 board and I think anyone would want OGS to be able to describe a 9x9 or other size game as using Japanese rules.

It’d probably be just as useful to specify the defaults for different board sizes, and link to the handicap komi, since it’s reduced on 9x9 as far as I remember.

I think if you’re doing this for each ruleset, then it makes sense to specify komi since Chinese/AGA tend to have different komi to Japanese.

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Animations for nigiri. Older on OGS grab stones in the bowl(the time pressing the button may fix how many of them), then other chose even vs odd (place one or two stones), then we check.

Some animations when scoring, according to each rule would be great too.

Nice idea but never going to happen :laughing: