Games played under the official Japanese rules also can have several different troublesome outcomes (that would challenge how our ladders and tournaments work):
- “No Result”, which means that the game did not end with a result. THIS IS NOT THE SAME AS JIGO. This outcome happens when the game gets stuck in a long cycle (such as triple ko, eternal life, etc.) that neither player is willing to break from.
- “Both Players Lose”, which is a really bizarre situation that arises when both players pass too early, while leaving an unsettled situation on the board that proves to be decisive to the outcome. See this post for more discussion: Odd Cases 🤔 in the Japanese Rules - #2 by yebellz
- If integer komi were allowed in some tournaments, “Jigo”, which is a drawn game due to a tied score.
However, currently, the OGS implementation does not support any of these outcomes properly. Further, there are trickier questions about how to really properly handle “No Result” and “Both Players Lose”, since those should not (in principle) be viewed the same way as a draw. Maybe we should exclude Japanese rules from certain (or all?) tournament formats, and ladders as well, until these issues can be properly resolved.