kovarex: @posetcay: Can you please show which variation you added? It still seems to look like just KO+ (instead of the original KO+2)
posetcay: I added G2-F2-D2-G1-E2, it was marked as wrong before, but I am not sure if that was the variation you were talking about in the other comment.
kovarex: Less then half a year later, I could transfer this problem to be status based to make it much clearer what is going on.
While I was checking this problem out, I discovered several issues:
1) The proper result of this seems to be KO+, and not KO+2, as whites answer in some of the variants was wrong.
In this position, white did answer to E2, which leads to the KO+2 indeed, but just taking the stone as in the updated tree, it leads to just the KO+
2) Some alternative orders of moves or refutations were missing:
P.S. If anyone wants to check these chagnes, I will welcome it.
posetcay: Black can still get an advantageous ko with proper order of moves, added the variations.
kovarex: Yes, but extra local threat has the same value of taking or not taking first. So I think it would be fair to only accept variants with the extra local ko threat.
d4rkm4tter: Sure, this is a KO+2 > KO+ case and we can say, only the KO+2 is correct. I'm starting to like the idea of good solution and best solution.
kovarex:
There is an interesting inconsistency in this problem.
KO- is ko where opponent takes first, KO+ is is when I take first, and KO+2 is when Opponent has to add one extra threat and I take first after that anyway.
KO- variation is marked wrong, as there is better KO+ variant.
But there is also KO+2 variant which is the "same correct" as just the KO+.
Shouldn't only the KO+2 be marked correct?
The KO+2 is for example:
S3, T3, T2, T1, N2, O2, Q2, P2, S1, R1, Q1, N1.
Now black takes the ko, and is leftwith the extra local threat at P1.
But Playing P1 before Q1 leads to a correct solution, where P1 was already played, and it is basically 1 local ko threat less.
posetcay: It is true that some variations have fewer local threats than others but any ko that attacker takes first is accepted here.
@posetcay: Can you please show which variation you added? It still seems to look like just KO+ (instead of the original KO+2)