(;AW[pc]AW[qc]AW[qe]AW[nc]AB[od]AW[mb]AW[lb]AW[lc]AW[ld]AW[le]AB[mc]AB[md]AB[me]AB[mf]AB[lf]AB[ke]AB[kd]AB[kc]AB[kb]AW[kf]AW[jf]AW[ie]AW[ic]C[Black to play]AP[goproblems]
(;B[ob]
(;W[nb];B[oc];W[jb]
(;B[la]C[If Black plays at 1, Black wins the capturing race by one move. If White plays 2 at 3, Black plays 3 at 2.RIGHT]LB[ob:1]LB[nb:2]LB[oc:3]LB[jb:4]LB[la:5];W[ja]
(;B[na];W[ka];B[nd];W[ma];B[la]C[RIGHT])
(;B[ka]C[RIGHT])
(;B[nd]C[RIGHT];W[ka]
(;B[na];W[ma];B[la]C[RIGHT])
(;B[ma];W[na])))
(;B[ma]C[];W[ka]
(;B[la];W[na];B[la];W[ma];B[nd];W[la])
(;B[na];W[la]))
(;B[na]C[];W[ka];B[la];W[ma];B[nd];W[oa];B[pa];W[ja];B[na];W[la])
(;B[nd]
(;W[ka]C[CHOICE]
(;B[na];W[la])
(;B[la];W[ma];B[oa];W[la])
(;B[ma];W[la];B[oa];W[ja])
(;B[oa];W[la];B[na];W[jd]))
(;W[jc]C[];B[na]))
(;B[ka]C[RIGHT]))
(;W[oc];B[nb]
(;W[na]
(;B[la]C[RIGHT])
(;B[ma];W[la]
(;B[ka]C[RIGHT])
(;B[oa];W[pb];B[ma]C[koCHOICE]))
(;B[pb]C[RIGHT])
(;B[oa]C[RIGHT]))
(;W[pb]
(;B[ma]C[RIGHT])
(;B[la]C[RIGHT]))))
(;B[oc];W[ob]C[Playing at 1 only helps White to link up his stones. The four black stones on the left are now dead.CHOICE]LB[oc:1]LB[ob:2]))