(;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 18 which is the problem
position. These do not represent a game sequence!]
;B[qr]
;W[pr]
;B[sr]
;W[pq]
;B[qs]
;W[pp]
;B[qp]
;W[po]
;B[rp]
;W[sp]
;B[so]
;W[ro]
;B[]
;W[rn]
;B[]
;W[pm]
;B[]
;W[nr]C[This is the problem position. Black to play and live.]
(;B[sq]
;W[qq]
;B[rq]
;W[rs]C[Failure: capturing the white stone is no good.])
(;B[qq]
;W[rs]
;B[rr]
;W[sq]
;B[rq]
;W[sp]C[Failure: enlarging the eye space is no good as white sacrifices a second stone on the edge to create a false eye.])
(;B[rr]
;W[qq]
;B[rq]C[Failure: easy death.])
(;B[ss]
;W[qq]
;B[rq]C[Failure: still dead.])
(;B[rs]C[CORRECT: playing the 2-1 point is often the correct move to make corner eyes.]
(;W[qq]
;B[rq]C[White can't stop the second eye.])
(;W[rq]
;B[qq]
;W[sq]
;B[rr]
;W[sp]
;B[sq]C[The throw-in is no good when three stones are sacrificed.])
(;W[sq]
;B[qq]
;W[rq]
;B[rr]
;W[sp]
;B[sq]C[The same result as the previous sequence.])))
