(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[9]KM[0.00]
PB[Noir]AW[df][cg][eg][fg][gg][hg][ig][ch][ih][di][ii]AB[ce][de][ee][ge][bf][ef][hf][bg][bh][bi][ci]
;B[dh]C[The cut is the only way to rediuce the space]
(;W[eh]
;B[ei]
;W[fi]
;B[gh]
;W[di]C[This is actually the right answer : White lives in ko])
(;W[ei]C[If White is not aware of the danger]
;B[eh]
;W[fi]
;B[fh]
;W[gi]
;B[gh]
;W[hi]
;B[dg]C[he is killed by this surprising sacrifice]
;W[hh]
(;B[fh]
(;W[eh]
;B[dg]
;W[dh]
;B[cf]C[using next this classical reduct-on of eye])
(;W[cf]
;B[dh]
;W[dg]
;B[eh]C[also dead]))
(;B[dg]
;W[dh]C[the order of moves is essential : here, white lives])))