(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[19]KM[0.00]
AW[pn][qn][nq][oq][qq][mr][nr][pr]AB[qo][ro][mp][np][op][pp][jq][mq][pq][lr][rr]LB[rr:A]C[Best defence for white following black 'A'.]
(;W[qr]
;B[rq]
(;W[os]LB[rr:A]C[RIGHT Black has made profit in the corner, and kept sente. This is the lowest price White pays for not completing the joseki at 'A'.])
(;W[qp]
;B[po]
;W[rp]
;B[sp]
;W[os]LB[rr:A]C[RIGHT Black has made profit in the corner, and kept sente. This is the lowest price White pays for not completing the joseki at 'A'.]))
(;W[rq]
;B[qr]
(;W[sr]
;B[ps]
(;W[or]
;B[rs]
(;W[os]
;B[ms]C[A bad ko for White.])
(;W[sq]
;B[ms]
;W[ss]
;B[qs]C[White is dead.]))
(;W[os]
;B[or]C[A bad ko for white.]))
(;W[qs]
;B[rs]
(;W[ms]
;B[ps]
;W[os]
;B[or]C[A bad ko for White.])
(;W[os]
;B[ps]C[A bad ko for White.])
(;W[sr]
;B[ps]
(;W[os]
;B[or]C[A bad ko for White.])
(;W[or]
;B[ms]C[White is dead.]))
(;W[ps]
;B[os]
;W[or]
;B[ms]C[White is dead.]))
(;W[rs]CR[rs]
(;B[ps]CR[ps]
(;W[or]CR[or]
;B[qs]CR[qs]
;W[sr]CR[sr]
;B[ss]CR[ss]
;W[sq]CR[sq]
;B[ms]CR[ms]
;W[rs]CR[rs]C[A bad ko for White.])
(;W[os]CR[os]C[A bad ko for White.]))
(;B[qs]CR[qs]C[If Black does not want ko........]
;W[ps]CR[ps]
;B[ss]CR[ss]
(;W[os]CR[os]
;B[rp]CR[rp]
;W[ms]CR[ms]C[White lives, but loses part of the group.])
(;W[sq]CR[sq]
;B[os]CR[os]
;W[or]CR[or]
;B[ms]CR[ms]C[White is dead.])))))