(;AB[bp]AB[cp]AB[dp]AB[cr]AB[ar]AW[bo]AW[co]AW[do]AW[ep]AW[eq]AW[dr]AW[fo]AW[hp]AW[bm]C[Can White regain the corner?]AP[goproblems]
(;W[bq]
(;B[cq]
(;W[bs]
(;B[cs]
(;W[br]C[Well done! (bA4 doesn't make it seki because W can force bA3 by surrounding)RIGHT])
(;W[ap];B[br]C[:(])
(;W[aq];B[ap]C[:(]))
(;B[br];W[cs]C[RIGHT]))
(;W[aq];B[br]C[:(])
(;W[cs];B[bs]C[:(])
(;W[ap];B[br]C[:(])
(;W[br];B[bs]C[:(]))
(;B[br];W[cq]C[RIGHT]))
(;W[bs];B[dq]
(;W[ds];B[er]
(;W[fr];B[cs]
(;W[es];B[br]C[:(])
(;W[br];B[es]C[:(]))
(;W[cs];B[fr]
(;W[br];B[bq];W[ap];B[es];W[cq]MA[cr]C[:(])
(;W[ap];B[br]C[:(])
(;W[gr];B[br]C[:(]))
(;W[br];B[es]
(;W[cs];B[bq];W[cq]MA[cr]C[:(])
(;W[fr];B[cs]C[:(])))
(;W[er];B[cs]
(;W[br];B[bq]C[:(])
(;W[ap];B[bq]C[:(])
(;W[bq];B[br];W[ap];B[cq]C[:(]))
(;W[es];B[cs]
(;W[br];B[bq]C[:(])
(;W[bq];B[br];W[ap];B[cq]C[:(])
(;W[ap];B[bq]C[:(]))
(;W[bq];B[br]C[:(]LB[ap:1]LB[cq:2]LB[cs:3]LB[er:4]LB[es:5]LB[fr:6])
(;W[br];B[er]
(;W[bq];B[ds]C[:(])
(;W[ds];B[es]
(;W[cs];B[bq];W[cq]MA[cr]C[:(])
(;W[bq];B[cs]C[:(]))
(;W[fr];B[ds]C[:(])
(;W[cs];B[ds]C[:(]))
(;W[cs];B[er]
(;W[ds];B[fr]
(;W[br];B[bq]
(;W[ap];B[es];W[cq]MA[cr]C[:(])
(;W[gr];B[es];W[cq]MA[cr]C[:(]))
(;W[ap];B[br]C[:(])
(;W[bq];B[br]C[:(]))
(;W[br];B[ds]C[:(])
(;W[fr];B[ds]C[:(]))
(;W[ap];B[bq]C[:(]
(;W[cs];B[er];W[es];B[fr]C[:(])
(;W[er];B[cs]C[:(])
(;W[ds];B[cs]C[:(])
(;W[es];B[cs]C[:(])))
(;W[br];B[bs]C[:(])
(;W[cs];B[bs]
(;W[cq];B[bq];W[br]C[:(]MA[cr])
(;W[bq];B[cq]C[:(])
(;W[dq];B[cq]C[:(])
(;W[aq];B[ap]C[:(])
(;W[ap];B[bq]C[:(]))
(;W[ds];B[bs]
(;W[cq];B[bq]C[:(])
(;W[bq];B[cq]C[:(])
(;W[aq];B[ap]C[:(]))
(;W[dq];B[bs]C[:(])
(;W[cq];B[bq]
(;W[dq];B[bs]C[:(])
(;W[bs];B[dq]
(;W[cs];B[er];W[es];B[fr]C[:(])
(;W[ds];B[cs]C[:(])
(;W[es];B[cs]C[:(])
(;W[er];B[cs]C[:(])))
(;W[aq];B[ap]
(;W[bq];B[br]C[:(])
(;W[cq];B[dq]C[:(])
(;W[br];B[bq]C[:(])
(;W[dq];B[cq]C[:(])
(;W[bs];B[cs]
(;W[br];B[bq]C[:(])
(;W[bq];B[cq]C[:(])
(;W[cq];B[dq]C[:(]))
(;W[cs];B[br]
(;W[bs];B[dq]
(;W[bq];B[er];W[es];B[fr]C[:(])
(;W[er];B[bq]C[:(])
(;W[es];B[bq]C[:(])
(;W[ds];B[bq]C[:(]))
(;W[bq];B[bs]C[:(])
(;W[cq];B[dq]C[:(])
(;W[dq];B[bs]C[:(])))
(;W[ap];B[bq]
(;W[dq];B[bs]C[:(])
(;W[bs];B[dq]
(;W[cs];B[er];W[es];B[fr]C[:(])
(;W[er];B[cs]C[:(])
(;W[ds];B[cs]C[:(])
(;W[es];B[cs]C[:(]))))