GSATE problem 99
the solution says 1 is hard to see and that white must pull back to 2 to make 2 eyes, and that black 3 is then sente.
KarlKnechtel: White has to 'pull back'? Why? I don't see any way of killing this shape.
ChessWhiz: Although I don't see a way to kill, this result is even better than the solution -- only 2 points for white, and black has sente. If instead at 5, at 4, putting half the group in atari and killing the rest.
Seems 1 threatens to kill white with a shortage of liberties, White is reduced yet another point in sente.