(;GM[1]FF[4]AP[glGo:1.4]ST[1]
SZ[19]KM[6.5]
PW[White]PB[Black]DT[2011-07-07]
AB[qb][rb][rc][qf][pf][pe][rg][sg][pd][pc][od][ne]AW[qc][rd][qd][qe][se][sf][rf][pb][pa][oc][nd][nc][nb][na]C[White to win the corner unconditionally.]
(;W[sb]
;B[sc]
(;W[ra]
;B[sa]
;W[qa]C[RIGHT Well done! Black cannot approach. White will wait until there are no ko threats left on the board, and then play t18 followed by t16.])
(;W[qa]
;B[ra]C[Seki])
(;W[sa]
;B[ra]))
(;W[sc]
;B[sb]
(;W[qa]
;B[sd]C[Two-step ko for white.])
(;W[ra]
;B[sd]C[Two-step ko for White.])
(;W[sa]
;B[sd]C[Two-step ko for White.]))
(;W[ra]
;B[qa]
(;W[sc]
;B[sa]C[Seki])
(;W[sb]
;B[sa]C[Ko]))
(;W[qa]
;B[sd]
;W[sc]
;B[sb]C[Ko])
(;W[sa]
;B[sd]
;W[sc]
;B[sb]C[Ko]))