kovarex: @TwT What is the point of the one final move added?
First of all, any other move (including pass) is still ok, as black has enough of liberties to kill the corner shape to be alive. So the only correct ove should be actually pass (do we have it already?) not a move.
posetcay: Ended the sequence at B1 (opponent's move).
Lyde: [current position] Player can pass here. Otherwise B16 can be exchanged earlier as well...
caranthir: [Twt: I know. If the last move isn't made by the player, it will immediately transition to the next variation without any delay. This might be ONLY frustrating for someone who isn't yet a MASTER.] The eyesore about the said last player move is just that it's not only not required but also not necessarily even sente (but should've been played at a point where capturing the two stones makes the group alive, ie. where it would've been sente). Therefore I'd prefer to leave out both the last player move and the preceding opponent move in that variation. But it's your call.
kovarex: @posetcay Ok, I added the variant. But I guess that you agree with the original change of the problem that the probe move needs to be first and with the 2 different ways to answer it.
posetcay: Yes, the alternative response mode works very well in this problem because there are 3 different answers to T6 and all 3 of them have different answers. By the way, T4 is the only move that lives after T7, S2 and Q1 both die, I will add refutations to them later.
posetcay: After S6-S7-T6-T7-S2-R1-Q1, S1 at S3 kills so I am not sure about current solution. If S2 is played at T4 I think it becomes ko with T4-S2-S1-R1-T2. R1 can't be at T2 because it becomes seki. Definetely an interesting problem.
posetcay: Actually if S2 is played at T4, black can live with T4-S2-T5 so that is the best answer I can find to opponent T7.
kovarex: Out of curiosity, I tried to figure out what happens when white chooses the third way to capture the stones, by T7.
Interestingly enough, it seems that this forces third unique answer in the corner (S1) to survive. I added the variations.
If I'm right, the problem is even more interesting ...
kovarex: When I re-checked this problem as I'm doing the second check of all the problems I added, I believe I discovered this problem solution was not quite correctly defined. I believe I figured out, that the main idea of the problem is, that after black T6, white can either R5 (as was the only answer in this problem originally), or T5. The R5 answer has the solution as was posted, but T5 requires a different approach, so black has to start threatening life in the corner by T2 instead of S1. This leads me to the conclusion, that the original alternative correct variation which started with S1 as the first move, should be now incorrect, as white will select the proper counter move to T6 (the T5) and prvent black from living. So I made the changes, and added both white answers in the "you need to answer both" to make the problem now more understandable to the solver. Some high dan should probably check if I'm right in the new variations.
Ended the sequence at B1 (opponent's move).