But that interpretation of passing for the ko "only once" does not handle both molasses ko (
https://senseis.xmp.net/?MolassesKo) and the following "long double ko seki" at the same time (as far as I understand, both cases should be seki under Japanese rules):
- Click Here To Show Diagram Code
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$$ | O O O O O O O X .
$$ | O X O . O . O X X
$$ | X . X O X O X O X
$$ | . X X X X X X O X
$$ | X X O O O O O O X
$$ | O O O . . . . . .
$$ | . . . . . . . . .
$$[/go]
If you understand passing-for-ko to mean each single ko-shape of marking specifically the two-intersections of the ko-stones, then you need to pass twice to free the two-stage-ko part of the seki, and this positions becomes seki. If you understand each "shape" like the two-stage-ko to be freed completely with a single ko pass, white dies instead.
For the molasses ko, it is the other way around: if you consider that you have to pass twice to completely free the two-stage ko, then one side is considered dead, while it is (anti)seki if a single pass frees the whole two-stage-ko shape. There is not time in these examples to "recapture the ko again later once it has become a normal-play-ko", so that rule does not change it.
These examples were discussed when creating the Katago rules, as the Katago rules use a version of the Japanese pass for ko rule for each specific pair of ko intersections and thus will consider one specific player to die in the molasses ko if left as is, creating a very small difference (there is a single recorded case of molasses ko in actual play, that happened in an amateur game).
The only way I see to handle both positions is that a pass actually acts like a "normal" play somewhere else and thus lifts all the related kos in the region. J2003 have a global ko pass doing precisely that, but then it seems that it can get some interference from the elusive "enable" rule, which is very hard to pinpoint exactly as to when a stone counts as enabled and when it does not. My feeling is that Japanese pros have an implicit notion of locality, and then consider each locality as "a single ko", even if it has 4 kos inside it like this example, it is "one ko" (one long double ko, say) on the board, and you pass for "it" specifically, to separate it from a bent4 in an opposite corner and such, but the whole shape is what you pass for.