OGS's Japanese rule about white passing stone first


#1

At the end of the game, I believe the normal sequence is: black’s last move, white’s last move, black passes by giving white a stone, white passes by giving black a stone. Then count the score.

If white passes first by giving black a stone, then black passes, white passes, essentially white is giving black two stones. This is fair, because in Japanese rule you lose one point if you place inside your own territory. And white is forced to play the last move (pass a stone or place inside your own, it’s the same thing) in order to make the moves from both sides even.

But on OGS, I realized even if I selected Japanese Rule, white could pass first and black then passes and then we enter the scoring phase. The system only counts prisoners captured in the game, not the 1 and 1 in the passing phase. (or 1 and 2 here as described) This gives white 1 point advantage in this situation.

Was this intended in coding OGS? Or is there something I missed?

Many thanks for your response.


#2

Please don’t mix rulesets. Also, don’t use mixed rulesets (AGA, I’m looking at you). :stuck_out_tongue_winking_eye:

J rules - play until all dame are filled, remove captures, fill opponent’s territory with em, arrange neatly into rectangles, place leftover stones in the middle, count. Bent four in the corner is dead, eyes in seki don’t count (I think many online scoring systems get this wrong). That’s it. You’re done. No nonsense.

AGA rules - convoluted mess of passing first/last, giving stones and other weird stuff going on.

Luckily Ing SST isn’t even available.


#3

You are describing AGA rules but attributing them to Japanese rules. No need for the extra pass in Japanese rules and a stone isn’t given to the opponent when you pass.

Even in AGA rules, if using Area scoring then the pass stones, and the “white moves last” rule are irrelevant (because the only reason they exist is to make sure the score is the same regardless of how you are scoring the game.)


#4

Digression: OGS actually implements the Chinese rule the Japanese way(by counting prisoners instead of counting stones). There’s a bug with forking lately( for like >half a year or so), all prisoners are reset to zero when you fork and even when you use Chinese rule, you might find yourself missing a few points due to the missing prisoner. So that’s something to be cautious of…

Example of a game that’s scored incorrectly: https://online-go.com/game/12457647 (score estimate works but the actual score is just wrong)


#5

smurph,

MY bad! I totally mixed up AGA with Japanese rule. I never tried AGA rule on OGS as I liked the simplicity of Japanese rule and I can count scores accurately during the game.

So is that in AGA white required to pass the last? Is that also implemented on OGS so that there may be 1 passing stone (prisoner) of black and two passing stone of white? (I still don’t know if this is necessary though)


#6

Yes, I was terribly inaccurate. I was mostly curious of the connotation from territory counting together with the passing stone rule.


#7

Shoot, I know I did :frowning: Ugh… that one is tricky to implement. Does stones inside a seki eye count as captured? I guess… not…?


#8

No, they’re all alive so no captures. The other tricky part is that in Chinese seki territory and stones ARE counted but in Japanese it’s all dame.

Maybe an easy way to think about it is treat all seki as dame and score it accordingly?


#9

With Japanese rules, you need to capture stones inside seki eyes, otherwise they will not count as prisoners. (I think?)