at
.
unkx80: This diagram looks ridiculous - captures five White stones, and hence
cannot be played on top of
.
unkx80: Then captures at a. How is this a failure diagram?
unkx80: Why is this an errata? May I assume that it is Black to play?
unkx80: If is indeed a White stone, then this is the solution, which results in a ko.
The theme of the problem is: Black will get an eye at the marked point, she must find a method of creating a second eye.
The marked point is not an eye. White will squeeze at 'a'. Black has only one eye.