(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[rn][ro][so][rp][pq][qq][sq][pr][ps]AB[qm][rm][qn][qo][qp][rq][qr][rr][qs]C[This is the problem position. Black to play]
(;B[ss]C[This is the move that allows black to live.
White does not have enough liberties
to capture the corner stones.]
(;W[sp]
;B[sm]
;W[sr]
;B[sn])
(;W[sm]
;B[sl]
;W[sp]
;B[sn])
(;W[sr]
;B[sp]
;W[sq]C[This gets white nowhere (and may
cause an illegal board repitition).]))
(;B[sr]
;W[ss]
(;B[sp]C[This black allows white to start a ko,
so is not as good.])
(;B[rs]
;W[ss]))
(;B[sm]C[Approaching from this side is too slow.]
;W[sr]
;B[sn]
;W[rs])
(;B[rs]
;W[sr]C[Obviously no good either.]))
