(;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 28 which is the problem position. These do not represent a game sequence!]
;B[rr]
;W[rq]
;B[rs]
;W[sr]
;B[sp]
;W[sq]
;B[qq]
;W[qr]
;B[pr]
;W[qp]
;B[pq]
;W[po]
;B[pp]
;W[qo]
;B[ps]
;W[op]
;B[oo]
;W[oq]
;B[on]
;W[or]
;B[pn]
;W[mp]
;B[pm]
;W[qn]
;B[qm]
;W[ro]
;B[rm]
;W[]C[This is the problem position. Black to play.]
(;B[qs]
;W[os]C[Black can never get to play at T1 even if he captures
at R1 first.])
(;B[rn]
;W[so]
;B[sn]
;W[rp]C[Because of the problem with T1 if he lets white
make an eye the position becomes seki (white
can't play T1 either). ])
(;B[so]C[This looks like giving up two stones, but...]
(;W[sn]
(;B[rn]
;W[rp]C[...after white takes two..]
;B[so]C[..black throws in.]
;W[os]
;B[qs]
;W[sp]
;B[sm]C[White still can't play T1 but black can take
the ko at T5 any time and white has no
way to win it.

So this sequence is the correct answer.])
(;B[sm]C[This black doesn't work - it's too slow]
;W[rp]
;B[rn]
;W[so]C[White gets the seki ]))
(;W[rp]
;B[sn]C[This is too easy for black])))
