(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[]PB[Black to Play]C[Just play through the moves to move 42 which is the problem
position. These do not represent a game sequence!]
;B[rq]
;W[rr]
;B[qq]
;W[qr]
;B[pq]
;W[pr]
;B[oq]
;W[or]
;B[nq]
;W[nr]
;B[op]
;W[pp]
;B[oo]
;W[qp]
;B[on]
;W[rp]
;B[pn]
;W[sr]
;B[qo]
;W[mq]
;B[mp]
;W[lq]
;B[mo]
;W[lp]
;B[no]
;W[lo]
;B[rn]
;W[ln]
;B[]
;W[nm]
;B[]
;W[om]
;B[]
;W[pm]
;B[]
;W[qm]
;B[]
;W[qn]
;B[]
;W[rl]
;B[]
;W[sm]C[This is the problem position. Black to play and live.]
(;B[ro]
;W[sq]C[Failure: white connects his three stones and black dies.])
(;B[sp]
(;W[so]
;B[ro]
;W[sq]C[Failure: again white connects.])
(;W[ro]C[White must not play here,]
;B[so]
;W[po]
;B[qo]C[as black captures by snap-back.]))
(;B[sq]
;W[ro]
;B[so]
;W[po]
;B[sp]
;W[qo]C[Failure: this time it is not a snap-back.])
(;B[po]
;W[sq]C[Failure: again white connects.])
(;B[so]C[CORRECT: White cannot connect his three stones.]
(;W[sq]
;B[sp]
;W[sn]
;B[ro]
;W[rm]
;B[po]C[Black captures and lives.])
(;W[ro]
;B[sp]
;W[po]
;B[qo]C[Snap-back again.])
(;W[sp]
;B[sq]
;W[ro]C[Self-atari!])))
