From Hikaru no Go. This was the problem on the poster they put up to attract strong players to their Go club. (It turns out they were wrong. Black can live! But black will make a mistake here so you can defeat him.)
(;SZ[19]AB[aq]AB[br]AB[bp]AB[dq]AB[ds]AW[ao]AW[ap]AW[bo]AW[co]AW[dp]AW[ep]AW[fq]AW[gp]AW[gr]AW[fs]C[The rest of the board is settled (black and white have no ko threats)... White to kill.... Use H5 for tenuki.]GM[1]FF[4]VW[]AP[Many Faces of Go version 12.010]HA[0]ST[0]DT[2011-05-19]KM[6.5]RU[Japanese]RE[W+T]PL[W]
(;W[bs]
(;B[as]C[CHOICE]
(;W[er]C[]
(;B[dr]C[CHOICE]
(;W[cq]C[];B[cr]C[]
(;W[bq]C[];B[cp]C[]
(;W[bq]C[];B[cq]C[];W[ar]C[RIGHT])
(;W[ar];B[bq]))
(;W[ar];B[bq];W[cp];B[cs]))
(;W[cr];B[cq];W[ar];B[bq])
(;W[cs];B[cr])
(;W[ar];B[bq];W[cq];B[cr];W[cp];B[cs]))
(;B[cs];W[cr]C[RIGHT])
(;B[cq];W[ar];B[bq];W[dr];B[cs];W[cr]C[RIGHT]))
(;W[cp];B[bq];W[ar];B[cs])
(;W[cq];B[cr];W[ar];B[bq];W[cp];B[cs])
(;W[ar];B[bq]
(;W[as];B[er])
(;W[er];B[cs])
(;W[cr];B[cq]))
(;W[cr];B[cq];W[ar];B[bq]))
(;B[ar];W[cq]C[RIGHT])
(;B[cs];W[as]
(;B[cp];W[cq];B[bq];W[dr]C[RIGHT])
(;B[cq];W[dr];B[er];W[es]C[RIGHT])))
(;W[cp];B[bq]C[])
(;W[cq];B[cr]C[])
(;W[cr];B[cq]C[])
(;W[dr];B[er]C[])
(;W[er];B[dr]C[])
(;W[as];B[bs]
(;W[cr];B[cq])
(;W[cq];B[cr]))
(;W[cs];B[cr]C[]))