(;AB[qc]AW[pd]AW[qd]AW[re]AW[qf]AB[rd]AB[rc]AB[pc]AW[oc]AB[ob]AB[nb]AW[nc]AW[mc]AW[mb]AW[na]AB[pb]AW[qa]LB[qa:A]AW[kb]C[White just played A.Black to play the best move.]AP[goproblems]
(;B[sd];W[sb]
(;B[rb];W[oa]
(;B[pa];W[ra]
(;B[ma];W[na]C[Sente seki is wrong.CHOICE]
(;B[sc];W[se];B[sa]C[Ko - not good enough])
(;B[qb];W[se];B[sa];W[ra]C[Bent four in the corner is dead, sorry]))
(;B[qb];W[ma]C[CHOICE];B[sa];W[ra]C[];B[sc];W[sa];B[qa];W[sa]C[Dead])
(;B[sc];W[ma]
(;B[sa]C[Ko - not good enough])
(;B[qb];W[se]C[Oops :-)])))
(;B[ra];W[pa]C[Dead]))
(;B[ra];W[rb]
(;B[oa];W[ma]C[]
(;B[qb];W[sa]C[Seki - not good enough])
(;B[pa];W[sa]C[Dead]))
(;B[qb];W[sa];B[oa];W[ma]C[Seki - not good enough])
(;B[pa];W[sa]C[Dead])))
(;B[sb]
(;W[ra]
(;B[sd];W[rb]
(;B[pa]C[Life! Good job!RIGHT])
(;B[oa];W[ma]C[Seki is not good enough]
(;B[qb]C[];W[se]C[Seki - not good enough])
(;B[pa];W[se]C[Seki - not good enough]))
(;B[qb]
(;W[oa]C[CHOICE];B[pa]C[Life! Good job!RIGHT])
(;W[se]C[CHOICE]
(;B[pa]C[Life! Good job!RIGHT])
(;B[oa];W[ma]C[Seki - not good enough]))))
(;B[rb];W[sd]C[Dead]))
(;W[rb]C[CHOICE]
(;B[sd]
(;W[sa]C[Please remember that ko is unacceptable]
(;B[qb];W[sc];B[pa]C[RIGHT];W[se]
(;B[ra]C[Double ko life is not ideal, but I'll let it slide this time ;-)RIGHT])
(;B[sb]C[Double ko life is not ideal, but I'll let it slide this time ;-)RIGHT]))
(;B[pa];W[sc];B[qb]C[RIGHT];W[se]
(;B[ra]C[Double ko life is not ideal, but I'll let it slide this time ;-)RIGHT])
(;B[sb]C[Double ko life is not ideal, but I'll let it slide this time ;-)RIGHT]))
(;B[ra]C[Did you hear what I just said? Ko is not good enough]))
(;W[se]
(;B[qb];W[ra]
(;B[pa]C[Life! Good job!RIGHT])
(;B[oa];W[ma]C[Seki - not good enough]))
(;B[ra];W[sa]
(;B[qb];W[sc]C[Ko - not good enough])
(;B[pa];W[sc]C[Ko - not good enough]))))
(;B[qb];W[ra];B[sd]
(;W[oa]C[CHOICE];B[pa]C[Life! Good job!RIGHT])
(;W[se]C[CHOICE]
(;B[pa]C[Life! Good job!RIGHT])
(;B[oa];W[ma]C[Seki - not good enough])))
(;B[ra];W[sa]C[Please keep in mind that ko is not good enough]
(;B[qb];W[sc]
(;B[pa];W[sd];B[ra]C[Ko - not good enough])
(;B[sd];W[oa]
(;B[pa];W[se]C[Opps :-)])
(;B[sb]C[Ko - not good enough])))
(;B[sd];W[se]
(;B[qb];W[sc]C[Ko - not good enough])
(;B[oa];W[ma]
(;B[ra]C[A difficult many-step ko, but still not good enough])
(;B[qb];W[sc]C[Ko - not good enough]))))
(;B[sa])))
(;B[ra];W[rb]
(;B[sb];W[sa]C[Please keep in mind that ko is not good enough]
(;B[qb];W[sc]
(;B[pa];W[sd];B[ra]C[Ko - not good enough])
(;B[sd];W[oa]
(;B[pa];W[se]C[Opps :-)])
(;B[sb]C[Ko - not good enough])))
(;B[sd];W[se]
(;B[qb];W[sc]C[Ko - not good enough])
(;B[oa];W[ma]
(;B[ra]C[A difficult many-step ko, but still not good enough])
(;B[qb];W[sc]C[Ko - not good enough]))))
(;B[qb];W[sa]
(;B[sb];W[sc]
(;B[pa];W[sd];B[ra]C[Ko - not good enough])
(;B[sd];W[oa]
(;B[pa];W[se]C[Opps :-)])
(;B[sb]C[Ko - not good enough])))
(;B[sd];W[sb];B[oa];W[ma]C[Seki - not good enough])
(;B[pa];W[sd]
(;B[ra]C[Ko - not good enoughCHOICE])
(;B[sb];W[sc];B[ra]C[Ko - not good enough])
(;B[sc];W[ra];B[sb];W[ra]C[DeadCHOICE])))
(;B[sd];W[sb]
(;B[oa];W[ma]C[]
(;B[qb];W[sa]C[Seki - not good enough])
(;B[pa];W[sa]C[Dead]))
(;B[qb];W[sa])
(;B[pa];W[sa]C[Dead]))
(;B[oa];W[sd]
(;B[sb];W[sa]C[Ko - not good enough])
(;B[sc];W[sa]C[Dead])))
(;B[rb];W[ra]
(;B[sd];W[sb]C[Sente seki is wrong.]
(;B[oa]C[Sente seki is wrong.CHOICE])
(;B[pa];W[se]C[Sente seki is wrong.CHOICE]
(;B[sc]C[Ko - not good enough.CHOICE])
(;B[qb]C[Dead.CHOICE]))
(;B[qb];W[se]
(;B[oa]C[Sente seki is wrong.CHOICE])
(;B[pa]C[Dead.CHOICE]))
(;B[sc];W[oa];B[pa];W[ma]
(;B[sa]C[Ko - not good enough])
(;B[qb];W[se]C[Oops :-)])))
(;B[pa];W[sd];B[sc];W[sa]C[Bent four in the corner is dead, sorry])
(;B[sa];W[sb]
(;B[sc];W[se]
(;B[pa];W[sd]
(;B[sa]C[Ko - not good enough])
(;B[qb];W[oa]C[Oops :-)]))
(;B[qb];W[oa]
(;B[pa];W[sd]C[Oops :-)])
(;B[sa]C[Ko - not good enough])))
(;B[oa];W[ma]
(;B[sd]C[Neither seki not 100-year ko is good enough])
(;B[sc];W[sa];B[qb];W[se];B[pa];W[ra];B[sa];W[sb]C[Ko - not good enough])))
(;B[sc];W[oa];B[pa];W[sa]C[Bent four in the corner is dead, sorry])
(;B[oa];W[sd];B[sc];W[sa]C[Sente seki is wrong.])))