(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]C[Just play through the moves to move 18 which is the problem position. These do not represent a game sequence!]
;B[qr]
;W[rr]
;B[qq]
;W[pr]
;B[rq]
;W[qs]
;B[qp]
;W[pq]
;B[pp]
;W[op]
;B[oq]
;W[np]
;B[nq]
;W[mp]
;B[nr]
;W[mq]
;B[]
;W[mr]C[This is the problem position. Black to play.]
(;B[or]
;W[ps]C[Black cannot safely play atari...]
;B[sr]
;W[ns]
;B[rs]C[And capturing the stone first is not fast enough.])
(;B[sr]
;W[or]C[Clearly getting one stone this way is not enough])
(;B[ns]
;W[os]C[This fails as black still cannot safely atari white.])
(;B[os]C[Correct: This is the tesuji.]
(;W[or]C[White clearly cannot do this])
(;W[ps]C[This isn't fast enough - black can capture the stone
in time]
;B[sr]
;W[ms]
;B[rs]
;W[ns]
;B[or]C[Black gets all])
(;W[ms]C[Anything like this clearly also fails for white.])))
