:scratch: I'm confused. Could you perhaps restate the question?

I think he's talking about how passing twice ends the game. He is thinking about passing instead of finding a ko threat but he fears that the other player would also pass and end the game. Thus he wants to know how to resume the game in case both players pass during a ko fight.

Sometimes, after a game ends, the two players can't agree on which stones are dead or alive. Many rulesets have some allowances for the game to resume to help resolve such disputes. There's a couple of choices to make when writing such rules; for example: who plays first? may the first player retake a ko, if one is on the board? etc.

It seems like these questions might be easier to answer if we distinguish two different kinds of "pass" move. One is a move which definitely will not end the game, but which transfers play back to the other player; in particular, you can use this move if there is nothing useful for you to do on the board other than retake a ko, but you are not (yet) allowed to retake the ko. The other move is a declaration that you think the game is over; two of these in a row end the game (as two of any pass do in many rulesets). Of course this still gives the other player a chance to announce that they think the game is unfinished (by playing a stone).

I suppose I really have a few questions, like: are there any current rulesets that make this distinction (or one like it)? is my assertion that such a distinction would be useful actually true? are there any obvious problems with making such a distinction?

Ing was the first, I believe, to designate pass as a move.

Let me add that when I learned go we did not have passes. Games ended by agreement. We did not have any problems with that, but in the history of go problems occasionally arose.

the ambiguities arising from cycles

Robinson / Olmsted might have been the first, some five decades earlier.

On the rules level, avoiding ambiguity can be even simpler, using, e.g., positional superko. In terms of strategy, it is more appropriate to speak of "complexity".

I have not seen their writing.

Under Ing rules it takes four passes to end play, and that takes care of the problem of unfinished kos or superkos.

the first two passes mean "I have no worthwhile moves", while the second two passes mean "There are no dead stones left, we can score now."