Page 183, problem 751, problem diagram
Black to live
Page 183, problem 751, solution diagram
Black plays 1, sacrificing two stones. After White captures with 4, Black 5 makes a second eye.
Erratum: Black can just connect his stones at a or b since White cannot make a false eye on the left. This way he does not have to sacrifice two stones to live.
jvt: A new kind of problem: which stone to add or remove so that the solution makes sense. The diagram would have to be like this for the solution in Diag. 2, sacrificing two stones, to work and be unique.
PatrickB: If Black plays a in diagram 3...
White plays , making miai of a and b. Black is now dead. Similarly, if Black plays a in the original diagram, White just plays atari above his stone on the right and then connects at b. Again, Black is now dead.
PatrickB: Gah, you're right. Silly of me. I should have seen this. Is the proposed new diagram actually unique, though?
What if Black plays at instead of sacrificing two stones here? Without a white stone in the corner at a causing shortage of libertis, Black can now play at
, yielding:
Leaving this, with a and b miai, Black alive, and again no unique solution requiring sacrificing two stones...
unkx80: Dead.
Gah again. This is what I get for wiki-ing at 3:30 AM. Pardon my stupidity.