(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[np][op][nq][pq][qq][nr][or][rr][rs]AB[mo][no][oo][mp][pp][qp][rp][mq][rq][mr][sr][ms][ns]C[Black to play and kill]
(;B[qr]C[This move is wrong]
(;W[pr]C[However White must not answer it here.]
;B[ps]
;W[qs]
;B[os])
(;W[ps]C[This is the correct response and white lives]))
(;B[pr]C[This fails too.]
;W[ps]
;B[os]
;W[qr])
(;B[os]
;W[ps]
;B[qr]C[This is not a threat and white lives]
;W[rm]
;B[sq]
;W[pr]
;B[ss]
;W[qs])
(;B[ps]C[This move both threatens to escape or catch white
short of liberties]
(;W[pr]
;B[os]C[Only one eye])
(;W[os]
;B[pr]
;W[oq]
;B[qr]C[White is captured.])))
