(;SZ[19]AW[bm]AW[bn]AW[bo]AW[bp]AW[cp]AW[cq]AW[cr]AW[cs]AB[bj]AB[bl]AB[cl]AB[am]AB[cm]AB[an]AB[en]AB[co]AB[do]AB[bq]AB[eq]AB[br]AB[er]GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Japanese]KM[0.00]PL[W]
(;W[ar]
(;B[ao]
(;W[ap];B[al];W[bs]C[white is alive (6 points)RIGHT])
(;W[bs]C[best for both, white is alive with at least 5 points (probably with 6, because A4 is only 1p gote for black).CHOICERIGHT]))
(;B[ap]C[good for white]
(;W[ao]C[white is alive (9 points, bad for b)RIGHT])
(;W[aq]C[RIGHT];B[as]
(;W[ao]C[white is alive (11 points, bad for b)RIGHT])
(;W[aq];B[ar]
(;W[ao]C[white is alive (12 points, bad for b)RIGHT])
(;W[bs];B[ao];W[aq];B[al]
(;W[ar]C[white is alive (7points, bad for b)RIGHT])
(;W[br]C[white is alive (7 points, bad for b)RIGHT])))))
(;B[aq]C[good for white]
(;W[ap];B[as];W[bs]C[white is alive (9 points, black will not play this way)RIGHT])
(;W[ao];B[as];W[bs];B[ar]
(;W[al];B[am]C[dead])
(;W[ap];B[ar]))
(;W[bs]C[white is alive (9 points)];B[as];W[ap]C[white is alive (9 points, bad for black)RIGHT]))
(;B[bs]C[good for white]
(;W[aq];B[ao]C[dead])
(;W[ao]C[aliveRIGHT])))
(;W[aq]
(;B[ar]C[dead]
(;W[bs];B[ap]
(;W[ao];B[aq]C[dead];W[as];B[aq];W[al];B[am]C[dead])
(;W[as];B[aq];W[ao];B[aq];W[al];B[am]C[dead]))
(;W[ap]C[death in gote?])
(;W[ao];B[ap]C[ko, black takes first]LB[ej:threat]LB[fj:ans];W[ej]LB[fj:ans];B[fj]LB[fk:threat]LB[ek:ans];W[aq]LB[fk:threat]LB[ek:ans];B[fk]LB[ek:ans]
(;W[bs];B[ap];W[as]C[white is alive, but black takes the ko];B[ek]C[white is alive, but black takes the ko])
(;W[ek];B[ap]LB[el:threat];W[el];B[aq]C[white is dead, but takes the ko];W[fl]C[white is dead, but takes the ko])))
(;B[ao]
(;W[ar];B[bs]C[dead])
(;W[bs];B[ar]C[dead])
(;W[ap];B[al]C[dead])))
(;W[ao];B[aq]
(;W[as];B[ar]C[dead])
(;W[bs];B[ar]C[dead])
(;W[ar];B[as]
(;W[bs];B[ar]C[dead]
(;W[al];B[am]C[dead])
(;W[ap];B[ar]))
(;W[ap];B[ar]C[dead])))
(;W[bs];B[ar]
(;W[ao];B[aq]C[dead])
(;W[ap];B[aq]C[dead])
(;W[aq];B[ap];W[ao];B[aq]C[dead];W[as];B[aq];W[al];B[am]C[dead])
(;W[as]
(;B[ao]C[dead])
(;B[aq]C[dead (one threat less than with B A5)])))
(;W[as];B[ar];W[aq];B[ap];W[bs];B[aq];W[ao];B[aq]C[dead];W[al];B[am]C[dead]))