A bug in the smallest boardsize (resolved: not a bug, a feature :) )

I tried whether it is possible to play to loose in Go;
and in order to shorten the experiment we used the smallest board possible.
Game Finished (online-go.com)

What puzzled me is that it should have stopped me from placing a stone when white just took out my last one - but I could play right away again on that very same spot.
Shouldnโ€™t the KO-rule prohibit this game turning into an endless game?

If you want to know what I am talking about replay the game and go to move 5, then 6 taking me, but in move 7 I can replay B2 right again.

๐”—๐”ฅ๐”ข ๐”ค๐”ž๐”ช๐”ข ๐”ฆ๐”ฐ ๐”ญ๐”ฏ๐”ฆ๐”ณ๐”ž๐”ฑ๐”ข, ๐”ด๐”ข ๐” ๐”ž๐”ซโ€™๐”ฑ ๐”ฌ๐”ญ๐”ข๐”ซ ๐”ฆ๐”ฑ.

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Youโ€™re playing with Japanese rules, which only has the ko rule that a board position may not repeat the one from two moves ago. So, youโ€™re not allowed to recapture a ko. But, longer cycles are allowed, such as triple koโ€™s (usually this will end the game in a โ€œno resultโ€ by some arbiter).

Prohibiting repetition of any previous board state is called โ€œsuperkoโ€, which comes in several flavours. The Chinese ruleset uses superko, so if you were to play your game under Chinese rules, then I expect it to be ending.


thanks, this is really interesting and sheds a light on the different rules.

Canโ€™t access the game