YeGO wrote:
In the J89 rules, there's a curious position mentioned in the commentary:
- Click Here To Show Diagram Code
[go]$$B Anti-Seki
$$ -------------
$$ | X O M X O .
$$ | . X X X O .
$$ | X X O O O .
$$ | O O O , . .
$$ | . . . . . .[/go]
Why is the position not just a potential "both players lose" situation?
1. If the game completely ends with this shape remaining, it will be an anti-seki. (How is that possible? see item 3.)
2. Let us assume that both players were willing to touch this corner but they simply forgot to do so before the game stops by two passes.
The current Japanese rule expects that at least one player will ask "resumption of game" which means the opponent can play the first move. If i) both players declines to do such a request, and ii) they also don't want to end the game leaving this corner as an anti-seki, both players lose.
i) and ii) are the conditions for both players to lose.
3. I guess your real question is how anti-seki can remain on the board if two players are reasonable. Such a situation is possible by the following scenario.
Assume Black has many ko threats. White knows that it is hopeless to try to win this ko, but after careful counting, he realizes that he can win the game by 0.5 points if Black plays at X and finish the game. So White passes expecting Black to play at X. Now Black doesn't want to lose, thus he also passes, claiming that he has 4 points at this corner, not 3 points.
This is clearly different from the situation in item 2 where something is left by mistake. They intentionally chose this strategy and they are not willing to make a reinforcement even when one's opponent asks for the resumption of the game.
Unfortunately to Black, Black has the right to leave this shape and end the game, but he cannot collect 4 points because of the anti-seki rule. In this case, the rulemaker is secretly shouting Black that "You can't gain one point by not playing at X, so play at X!".
_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at
https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5