My Go Rules Proposal: Commentary

Sekis

As with many similar short rulesets, this one does not define the concept of "seki" (mutual life) either. This is because it's not necessary: The concept of mutual life is just a side-effect of the rules and does not need to be mentioned explicitly.

At the dead stone removal stage both players have to agree which groups are alive and which are dead. If one of the players claims a group of his opponent is dead and his opponent disagrees, he must capture that group explicitly (he can do so freely because of the pass-stones additional rule).

If he is unable to capture the opponent group (or refuses to do so), then that group is simply alive. In the case of seki, both involved groups are in this situation (neither player can demonstrably capture the other group) and thus both groups are alive.

Although it's important to understand the concept of mutual life, this kind of information belongs to a Go tutorial (or rule commentary) and it's not necessary to explicitly mention this in the rules.

Because of the generic nature of the ruleset, where sekis are not handled in any special way, eyes in sekis do give points to the players as any other surrounded territory does. There are only quite few cases where this changes the score difference compared to the Japanese rules, but that should not be all that important.

Bent-4 in the corner

The bent-four-in-the-corner case is not handled in any special way by this ruleset (as it isn't in most other rulesets) because it's not necessary either.

In order to understand how this ruleset (and many other similar rulesets) handles the bent-four-in-the-corner situations, here is a clarifying explanation:

If such a situation is left to be decided at the dead stone removal stage, there are basically two possibilities:

  1. Both players agree that the bent-4 group is dead.

    This is simply the case when there are no unremovable ko-threats on the board and the owner of the bent-4 group agrees with this.

  2. The owner of the bent-4 group claims it is not dead as it stands but must be played explicitly, while the opponent claims it's dead.

    By rule 14 the owner of the group gets to play first (although in this case it usually doesn't really matter; usually he will just pass). Then one of the following four things can happen:

    1. If there are no unremovable ko-threats elsewhere, the opponent can simply remove all ko-threats from the board and then capture the bent-4 group at no cost (because of rule 14b, the so-called pass-stones rule).
    2. There's a double-ko seki elsewhere on the board providing an infinite amount of unremovable ko-threats: In this case the opponent can still capture the bent-4 group because of rule 14a (the so-called superko rule). This is because after making two threats in the double-ko seki, the rule 14b forbids making a third one (because it would repeat an earlier board position).
    3. There's an unremovable ko-threat elsewhere (usually a seki): When the bent-4 situation is played out, the owner of the group can make a threat in the other place. The opponent must decide whether he wants to respond to the threat or capture the bent4 group (just as in normal play).
    4. There's an unremovable ko-threat elsewhere, and because of it the opponent simply refuses to play the bent-4 situation. Since he thus failed to capture the bent-4 group, it is alive (and basically forms a seki with the invading opponent stones).

Thus it is possible for a bent-four-in-the-corner group to be alive if the opponent refuses to capture it explicitly when requested.

(There are, of course, even more complicated bent-four-in-the-corner situation, but there shouldn't be any problem with them regarding this ruleset.)


Copyright 2004 Juha Nieminen


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