unkx80: I am not sure whether the above diagrams count as solution. I believe it might count as a solution on the condition that following ladder does not work for Black.
Dave: I thought there was more but now it seems you are right.
a and b miai. Black c, White plays at . Black dies.
SnotNose: a and b aren't miai. White always has d to take away the eye at the edge.
unkx80: Besides, what happens when is played at instead?
Dave: I can't figure out how Black lives against this . However, it should not be the answer as there is no reason that I can see for the marked stone to be in the problem if kills.
Dave: We descend to the edge. This puts meaning back into the marked stone at least :-) First let's look at that troublesome diagonal play that spoiled my last idea... After , White pulls back at a. The marked stone is in exactly the right spot!
Dave: If here White can not play at . After capturing two stones or are miai to make the point at b an eye.
Dave: The diffence between this and the play at a analyzed at the top of this page is that after here there is no play at b and it is impossible to set up the ladder that unkx80 showed us above.
Dave: In answer to White plays b rather than a and there is no eye there.
unkx80: Both of you have got it for both the problems. =)
Dave: Note for readers. Sometimes we see the advice that we should solve problems in our heads to get the most out of them. That is what I normally do when I go through books (of course it is a little hard to carry a board on the subway :-). But our brains alone will only carry us so far - or else we would all be 9 dans, right? Sometimes you just need to dig if you are have any hope of solving it. I analyzed this problem in CGoban. The resulting sgf file (just variations, no text) is 8KB - as long as some reviews that I have written for the go teaching ladder. Sometimes there is no substitute for persistence :-)