(;AW[rp]AW[sp]AW[pq]AW[qq]AW[sq]AW[mr]AW[nr]AW[or]AW[ms]AB[qn]AB[ro]AB[so]AB[pp]AB[qp]AB[lq]AB[mq]AB[nq]AB[oq]AB[lr]AB[ls]C[Black to play.]
(;B[sr];W[rq]
(;B[pr];W[qr]
(;B[qs];W[ps]
(;B[rs]C[];W[pr];B[os];W[ns]C[This is not best. It is seki but white has captured 2 stones.])
(;B[rr];W[rs]))
(;B[ps];W[qs];B[rs];W[os]))
(;B[rr];W[qs])
(;B[qs];W[pr]
(;B[rr];W[qr])
(;B[rs];W[ps]
(;B[rr];W[qr])
(;B[os];W[rr]))))
(;B[pr];W[qr]
(;B[sr];W[rq]
(;B[qs];W[ps]
(;B[rs]C[];W[pr];B[os];W[ns]C[This is not best. It is seki, but white has captured two stones.])
(;B[rr];W[rs]))
(;B[rr];W[ps]))
(;B[rr];W[rq];B[qs];W[ps])
(;B[qs];W[ps];B[sr];W[rq];B[rs]C[];W[pr];B[os];W[ns]C[This is not best. It is a seki but white has captured two stones.]))
(;B[ps];W[qr]
(;B[rr];W[rq];B[qs];W[sr];B[rs];W[os]C[White lives with territory.])
(;B[sr];W[rq]
(;B[pr];W[qs]
(;B[os];W[ns]
(;B[ps]
(;W[rr]C[White lives with territory.])
(;W[pr];B[rs]C[This would be a failure for white.]))
(;B[rs];W[ps]C[White lives with territory.]))
(;B[rs];W[os]))
(;B[qs];W[rs])
(;B[rs];W[qs];B[os]C[This is a gote seki (for black) but white can capture the stones at P1/Q1 and black has to sacrifice another stone to be alive in a seki. In the correct solution black can get a seki without sacrificing stones.]))
(;B[pr];W[qs]))
(;B[qs];W[pr]
(;B[rr];W[rq];B[ps]C[];W[qr];B[os];W[sr];B[rs]C[ Seki.RIGHT])
(;B[sr];W[rq]
(;B[rr];W[qr]C[White lives with territory.])
(;B[rs];W[ps]C[White lives with territory.]
(;B[rr];W[qr])
(;B[os];W[rr]))
(;B[ps];W[rs];B[rr];W[qr])))
(;B[rs];W[ps]
(;B[sr];W[rq];B[qs];W[pr]C[White lives with territory.]
(;B[rr];W[qr])
(;B[os];W[rr]))
(;B[qs];W[pr]C[White lives with territory.])
(;B[pr];W[qr];B[sr];W[rq];B[qs]C[];W[pr];B[os];W[ns]C[This is not best. It is seki but white has captured two stones.]))
(;B[rr];W[rq]
(;B[qs];W[pr]
(;B[ps];W[qr];B[os];W[sr];B[rs]C[ Seki.RIGHT])
(;B[sr];W[qr]))
(;B[ps];W[qr];B[qs];W[sr];B[rs];W[os]C[White lives with territory])))