invalid problem set
Problem 4009
Created 2004-02-29
Source NHK Igo-no-jikan 2004.02.28
Rating
Difficulty 5 dan
Average Solve Time 82 secs
User Attempts
263 / 1883
Solve Ratio Rating 2 dan
rating history
The original problem is, the R18 being empty, "Can black tenuki to kill?". The answer is yes. But it is too difficult, so I restricted the first white move to R18 and made the goal "black to kill".
(;AW[qb]AW[pc]AW[oc]AW[qd]AW[rd]AB[rf]AB[re]AB[qe]AB[pd]AB[od]AB[nd]AB[nc]AB[nb]AB[pe]C[black to kill. ko is not good.]AP[goproblems]
(;B[ob]
(;W[pb]
(;B[rc];W[sd]
(;B[rb];W[sb]
(;B[ra];W[qc]
(;B[pa]C[RIGHT])
(;B[se];W[pa]
(;B[sc]C[RIGHT])
(;B[oa];W[sc]C[seki.])
(;B[sa];W[sc])
(;B[qa];W[sc]))
(;B[sc];W[qa])
(;B[sa];W[qa])
(;B[qa];W[pa]
(;B[se];W[sc])
(;B[oa];W[sc]))
(;B[oa];W[pa]
(;B[sc]C[RIGHT])
(;B[se];W[sc]C[seki])
(;B[qa];W[sc])))
(;B[qc];W[ra])
(;B[sc];W[ra]C[ko.])
(;B[pa];W[ra])
(;B[qa];W[pa]
(;B[sc];W[ra]C[itte yose ko (black needs one approaching move).])
(;B[ra];W[qc]
(;B[se];W[sc])
(;B[oa];W[sc]))
(;B[qc];W[ra])
(;B[sa];W[ra])
(;B[se];W[ra])
(;B[oa];W[ra]))
(;B[sa];W[ra])
(;B[se];W[ra]))
(;B[qc];W[rb])
(;B[se];W[rb])
(;B[pa];W[rb]
(;B[qa];W[ra]
(;B[sb];W[sc])
(;B[sc];W[sb])
(;B[se];W[sc]))
(;B[ra];W[qa];B[sb];W[qc])
(;B[sb];W[sc])
(;B[sc];W[sb]
(;B[qa];W[ra])
(;B[ra];W[qa])
(;B[se];W[qc])))
(;B[qa];W[pa]
(;B[rb];W[ra]
(;B[sb];W[sc])
(;B[sc];W[qc])
(;B[se];W[qc];B[sb];W[sc])
(;B[oa];W[sb])
(;B[qc];W[sb]))
(;B[ra];W[rb]
(;B[sb];W[sc])
(;B[sc];W[sb]))
(;B[sb];W[rb])
(;B[qc];W[rb])
(;B[sc];W[rb])
(;B[se];W[rb])
(;B[oa];W[rb])
(;B[sa];W[rb]))
(;B[sc];W[rb]
(;B[pa];W[sb]
(;B[qa];W[ra])
(;B[ra];W[qa])
(;B[se];W[qc]))
(;B[sb];W[pa])
(;B[ra];W[sb])
(;B[se];W[qc]))
(;B[ra];W[rb]
(;B[sb];W[sc])
(;B[sc];W[sb])
(;B[pa];W[qa];B[sb];W[qc]))
(;B[sb];W[rb]
(;B[pa];W[qa]
(;B[ra];W[qc])
(;B[sc];W[qc]))
(;B[ra];W[pa])))
(;B[sd];W[rc]
(;B[rb];W[sb])
(;B[sb];W[sc];B[rb];W[se]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[ra];W[sc]
(;B[rb];W[qa])
(;B[pa];W[qa]
(;B[rb];W[oa])
(;B[sb];W[oa]))
(;B[sb];W[qa])
(;B[qa];W[pa]
(;B[rb];W[sb])
(;B[sb];W[rb])))
(;B[pa];W[qa]
(;B[sb];W[sc]
(;B[rb];W[se])
(;B[ra];W[se]))
(;B[rb];W[sb]))
(;B[sc];W[sb]))
(;B[sc];W[rc]
(;B[sd];W[sb])
(;B[rb];W[ra]
(;B[sd];W[sb])
(;B[sb];W[sd])))
(;B[rb];W[rc]
(;B[sc];W[ra]
(;B[sb];W[sd])
(;B[sd];W[sb]))
(;B[qa];W[sb]
(;B[pa];W[ra])
(;B[ra];W[pa]))
(;B[sb];W[sc])
(;B[ra];W[qa])
(;B[sd];W[sb])
(;B[pa];W[ra]))
(;B[sb];W[rc]
(;B[rb];W[sc])
(;B[sd];W[sc];B[rb];W[se]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[ra];W[qa]
(;B[sc];W[sd])
(;B[rb];W[sc])
(;B[sd];W[sc]))
(;B[sc];W[sd])
(;B[pa];W[qa]))
(;B[ra];W[rb])
(;B[qa];W[pa])
(;B[pa];W[rb]))
(;W[sb];B[ra];W[pb];B[rb]
(;W[rc]
(;B[pa]C[RIGHT])
(;B[sd];W[qa]))
(;W[pa];B[rc]
(;W[sd]
(;B[qc]C[RIGHT])
(;B[sc]C[RIGHT]))
(;W[sc];B[qc]C[RIGHT])
(;W[qc]
(;B[sd]C[RIGHT])
(;B[sc]C[RIGHT])))
(;W[qa];B[rc]C[RIGHT])))
(;B[oa];W[sb]
(;B[ra];W[pb]
(;B[rc];W[rb]
(;B[sd];W[qc])
(;B[pa];W[qa])
(;B[qa];W[pa]))
(;B[qa];W[pa])
(;B[pa];W[qa])
(;B[rb];W[rc]
(;B[sd];W[qa])
(;B[qa];W[pa])
(;B[pa];W[qa])
(;B[ob];W[qa]))
(;B[sd];W[rb]
(;B[rc];W[qc])
(;B[sc];W[rc]))
(;B[sc];W[rb]
(;B[sd];W[rc])
(;B[rc];W[sd])
(;B[qa];W[pa])
(;B[pa];W[qa]))
(;B[ob];W[rb]))
(;B[rc];W[rb]
(;B[sd];W[qc])
(;B[sc];W[sd])
(;B[qc];W[sc]
(;B[qc];W[pb])
(;B[pb];W[qc])
(;B[qa];W[pb]))
(;B[pb];W[qc])
(;B[qa];W[pb]
(;B[pa];W[ra];B[sd];W[qc])
(;B[sd];W[qc]))
(;B[ra];W[pa];B[sd];W[qc]))
(;B[sd];W[rc]
(;B[pb];W[ra])
(;B[ra];W[pb]
(;B[rb];W[qa])
(;B[qa];W[pa])
(;B[pa];W[qa]))
(;B[qa];W[pb]
(;B[pa];W[ra])
(;B[ra];W[pa]))
(;B[pa];W[ra]))
(;B[sc];W[sd])
(;B[pb];W[ra]
(;B[rc];W[qc];B[sd];W[sc])
(;B[qc];W[rc])
(;B[sd];W[sc])
(;B[ob];W[qc]))
(;B[qa];W[ra])
(;B[rb];W[ra])
(;B[qc];W[rc])
(;B[pa];W[qa]))
(;B[rc];W[rb]
(;B[sd];W[qc]
(;B[sb];W[sc]C[direct ko.])
(;B[sc];W[sb]
(;B[se];W[ob])
(;B[ob];W[se])
(;B[oa];W[se])
(;B[pa];W[se])
(;B[ra];W[se])
(;B[qa];W[se]))
(;B[ob];W[sc])
(;B[oa];W[sc])
(;B[pa];W[sc])
(;B[qa];W[sc])
(;B[ra];W[sc])
(;B[se];W[sc]))
(;B[ob];W[sc])
(;B[pb];W[sc])
(;B[sb];W[sd]
(;B[sc];W[ob])
(;B[ob];W[sc])
(;B[pb];W[ob])
(;B[ra];W[pa])
(;B[pa];W[sc])
(;B[oa];W[sc])
(;B[qa];W[pa]))
(;B[sc];W[sd])
(;B[qc];W[sc])
(;B[pa];W[sd])
(;B[oa];W[sd])
(;B[qa];W[sc])
(;B[ra];W[sd]))
(;B[sd];W[rc]
(;B[ob];W[pb]
(;B[rb];W[sb])
(;B[sb];W[sc];B[rb];W[se]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[sc];W[sb])
(;B[ra];W[sb]
(;B[rb];W[qa])
(;B[qa];W[pa])
(;B[pa];W[qa]))
(;B[pa];W[sb]
(;B[qa];W[ra])
(;B[ra];W[qa]))
(;B[qa];W[pa]))
(;B[pb];W[ob])
(;B[sb];W[sc]
(;B[rb];W[se]
(;B[ob];W[pb]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[pb];W[ob])
(;B[pa];W[ob]
(;B[oa];W[qa])
(;B[qa];W[oa];B[na];W[ra])
(;B[pb];W[oa]))
(;B[qa];W[pa]))
(;B[ob];W[pb]
(;B[rb];W[se]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[pa];W[qa];B[rb];W[se])
(;B[ra];W[qa])
(;B[qa];W[pa]))
(;B[pb];W[ob])
(;B[ra];W[pb];B[rb];W[se]))
(;B[sc];W[sb])
(;B[rb];W[sb];B[ra];W[ob])
(;B[ra];W[pb]
(;B[sc];W[sb])
(;B[sb];W[sc];B[rb];W[se])
(;B[rb];W[sb]
(;B[ob];W[qa])
(;B[pa];W[qa])
(;B[se];W[sc])))
(;B[pa];W[pb]
(;B[rb];W[sc]
(;B[sb];W[se])
(;B[ra];W[oa]))
(;B[sb];W[sc]
(;B[rb];W[se])
(;B[ra];W[qa])
(;B[oa];W[qa];B[rb];W[se])
(;B[ob];W[qa];B[rb];W[se])
(;B[qa];W[oa]))
(;B[ra];W[qa]
(;B[sc];W[sb])
(;B[sb];W[sc])
(;B[rb];W[sc]))
(;B[oa];W[qa]
(;B[sc];W[sb])
(;B[rb];W[sc]
(;B[sb];W[se])
(;B[ob];W[ra]))
(;B[sb];W[sc];B[rb];W[se]))
(;B[sc];W[sb])
(;B[qa];W[ra])
(;B[ob];W[qa]
(;B[sb];W[sc]
(;B[rb];W[se])
(;B[ra];W[se]))
(;B[rb];W[sb])))
(;B[oa];W[sb]
(;B[pb];W[ra])
(;B[ra];W[pb]
(;B[rb];W[qa])
(;B[qa];W[pa])
(;B[pa];W[qa]))
(;B[qa];W[ra])
(;B[pa];W[ra])
(;B[se];W[pb]))
(;B[qa];W[pa]))
(;B[sc];W[sd]
(;B[rb];W[rc]
(;B[se];W[sb])
(;B[sb];W[ra])
(;B[ob];W[sb])
(;B[ra];W[sb]))
(;B[rc];W[rb])
(;B[ob];W[sb])
(;B[pb];W[ob])
(;B[ra];W[rb])
(;B[sb];W[rb])
(;B[pa];W[qa])
(;B[qc];W[rc])
(;B[qa];W[pa])
(;B[oa];W[pa]))
(;B[rb];W[rc]
(;B[ob];W[pb]
(;B[sb];W[sc])
(;B[ra];W[qa])
(;B[sc];W[ra]
(;B[sb];W[sd])
(;B[sd];W[sb]))
(;B[qa];W[sb]
(;B[pa];W[ra])
(;B[ra];W[pa]))
(;B[pa];W[ra])
(;B[sd];W[sb]))
(;B[sb];W[sc])
(;B[ra];W[sb])
(;B[pb];W[ob])
(;B[qa];W[sb]
(;B[ra];W[pa])
(;B[pa];W[ra])
(;B[oa];W[ra])
(;B[pb];W[ra]))
(;B[pa];W[sb]
(;B[ra];W[qa]
(;B[pb];W[qc]
(;B[sd];W[ob])
(;B[ob];W[sd]))
(;B[sd];W[pb]))
(;B[sd];W[ra])
(;B[pb];W[ra])
(;B[qa];W[ra]))
(;B[sc];W[sd]
(;B[se];W[sb])
(;B[sb];W[ra])
(;B[ra];W[sb])
(;B[ob];W[pb]
(;B[se];W[sb])
(;B[sb];W[ra]))
(;B[pb];W[ob])
(;B[pa];W[sb])
(;B[qa];W[pa])
(;B[oa];W[pa]))
(;B[sd];W[sb];B[ra];W[ob]))
(;B[sb];W[rc]
(;B[ob];W[pb]
(;B[rb];W[sc])
(;B[ra];W[qa]
(;B[sc];W[sd])
(;B[rb];W[sc])
(;B[sd];W[sc]))
(;B[sd];W[sc];B[rb];W[se]
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[ra];W[qa]))
(;B[pa];W[qa])
(;B[qa];W[pa])
(;B[sc];W[sd]))
(;B[sd];W[sc];B[rb];W[se]
(;B[ob];W[pb])
(;B[pb];W[ob])
(;B[pa];W[ob]
(;B[oa];W[qa])
(;B[qa];W[oa];B[na];W[ra])
(;B[pb];W[oa]))
(;B[qa];W[pa]))
(;B[rb];W[sc])
(;B[ra];W[ob])
(;B[pa];W[qa];B[pb];W[ob]))
(;B[ra];W[rb])
(;B[pb];W[ob])
(;B[pa];W[sb]
(;B[rc];W[rb]
(;B[sd];W[qc])
(;B[qc];W[sc];B[qc];W[pb])
(;B[sc];W[sd]))
(;B[ra];W[qa]
(;B[rc];W[rb];B[sd];W[qc])
(;B[rb];W[rc]
(;B[pb];W[qc]
(;B[sd];W[ob])
(;B[ob];W[sd]))
(;B[sd];W[pb]))
(;B[sd];W[rc]
(;B[pb];W[ob])
(;B[ob];W[pb])
(;B[rb];W[pb]))
(;B[sc];W[sd])
(;B[qc];W[rc])
(;B[pb];W[ob])
(;B[ob];W[rb]
(;B[sd];W[pb]
(;B[rc];W[qc])
(;B[sc];W[rc])
(;B[qc];W[rc])
(;B[se];W[sc]))
(;B[qc];W[pb])
(;B[pb];W[qc]))
(;B[oa];W[rb]
(;B[sd];W[pb]
(;B[rc];W[qc])
(;B[sc];W[rc])
(;B[se];W[sc])
(;B[qc];W[rc]))
(;B[qc];W[pb])
(;B[pb];W[qc])))
(;B[sd];W[rc]
(;B[ra];W[qa]
(;B[pb];W[ob])
(;B[ob];W[pb])
(;B[oa];W[pb]))
(;B[qa];W[ra])
(;B[pb];W[ra]))
(;B[pb];W[qc];B[ra];W[qa];B[sd];W[ob]))
(;B[qc];W[rc]))
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