(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White to play]C[Just play through the moves to move 18 which is the problem position. These do not represent a game sequence!]
;B[bc]
;W[cc]
;B[cd]
;W[dc]
;B[dd]
;W[cb]
;B[bd]
;W[ed]
;B[ec]
;W[fd]
;B[fc]
;W[gc]
;B[eb]
;W[gd]
;B[gb]
;W[hb]
;B[]
;W[ic]C[This is the problem position. White to play.]
;B[]
;W[da]C[This is correct - it is often a clever way of gaining a
liberty when potential eyes are involved.]
(;B[bb]
;W[fa]C[This is the follow up tesuji - important to stop
black making an eye here]
;B[db]C[This is atari...]
;W[ca]C[.. but white escapes.]
;B[ba]
;W[ea]C[Black is captured.])
(;B[fa]C[If black makes the eye...]
;W[ea]C[... then this for white makes it false.]
;B[bb]
;W[ba]
;B[ab]C[Black can't play the corner immediately because
it would be self-atari]
;W[ha]
;B[aa]
;W[ga]
;B[ca]C[This sets up a ko]
;W[fb]
;B[db]C[If white cannot win the ko he can get a few
points by making the exchange. ]))
