(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[om][pm][qm][mn][nn][lo][lp][qp][rp][mq][pq][rq][mr][nr][pr][rr][rs]AB[on][pn][no][qo][kp][mp][np][op][pp][jq][lq][nq][lr][qr][ls][qs]C[This is the problem position. Black to play]VW[]
;B[or]LB[oq:A][os:B]C[Black needs to join most of his stones up, but
probably can't save all. The wedge, here, is 
the obvious first move.]
(;W[oq]
;B[os]C[When black plays here it is self-atari for white 
to atari the two black stones from either side.]
;W[qq]C[If white threatens to take the two annoying stones in the corner by playing here next....]
;B[ns]
;W[ps]
;B[ms]C[... Black has time to capture the three white ones
and escape at the cost of just two stones.])
(;W[os]
(;B[oq]LB[qq:B][ns:A]C[In this position white A does not escape because of shortage
of liberties and white B leaves a snapback shape.]
(;W[ns]
;B[ms]
;W[ps]
;B[qq])
(;W[qq]
;B[ns]
;W[ms]
;B[ns]
;W[ps]))
(;B[ns]C[If black tries the snapback shape immediately....]
;W[oq]
;B[ms]
;W[or]C[... then white escapes])
(;B[ms]
;W[oq]
;B[ns]
;W[or]C[This way is also wrong for black.])))
