Pass For Ko

A "pass for a particular ko" is a special move type, used in Japanese Rules during hypothetical play for dispute settlement. The rules state that in the move sequences considered for that purpose, retaking a ko (that the opponent took earlier in the sequence) is not allowed like in normal play. Instead of playing regular ko threats, a player can only regain the right to recapture in that ko after making a pass for that particular ko (giving the opponent an extra opportunity to win the ko).

This rule is used to determine life and death without letting different kos influence each other, and without allowing groups to rely on ko threats for their survival.

(It is not clear if later recaptures by the same player in the same ko require further passes for that ko, or if this regained right to recapture in that ko is permanent and normal ko threats are sufficient there afterwards. Another unclear detail is how "that ko" should be interpreted if the ko mouth itself is destroyed/rebuilt during hypothetical play, in a multi stage ko for example. The rebuilt ko could be either seen as the same ko or as a new ko.)

jann: It should be noted that the rules only work well under the interpretation that passing for a ko is a one-time action that permanently removes its recapture restriction (reverting the ko to a normal ko for the passing player). Otherwise a double ko could be used to obstruct confirmation play elsewhere (by forcing a continuous pass-recapture cycle in it).

Although J89 is not completely clear on this, its commentary (on article 7) includes a hint which might support this view:

When the game stops, ko recapturing also stops.
...
If a player whose stone has been captured in a ko has passed for that particular ko, the situation for that ko is the same as if the game had been resumed: the player may now capture in that ko again.