(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]C[Just play through the moves to move 28 which is the problem position. These do not represent a game sequence!]
;B[pr]
;W[pq]
;B[qr]
;W[qq]
;B[rq]
;W[rp]
;B[sq]
;W[qp]
;B[rs]
;W[or]
;B[oq]
;W[ps]
;B[op]
;W[nr]
;B[pp]
;W[po]
;B[oo]
;W[om]
;B[]
;W[pl]
;B[]
;W[ql]
;B[]
;W[rl]
;B[]
;W[mq]
;B[]
;W[kq]C[This is the problem position. Black to play.]
(;B[sr]C[Black can sumply play here to make 2 eyes - but he 
should be able to do better and link up to the 4
black stones by capturing.
])
(;B[qo]C[This atari looks promising...]
;W[ro]
;B[pn]
;W[rn]C[But white just lets 1 stone be captured and black
has failed. ]
;B[sr]
;W[mn]C[The corner lives but the outside stones are lost.])
(;B[ro]C[This move threatens the double atari...]
;W[qo]
;B[pn]
;W[qn]
;B[qm]
;W[pm]
;B[rn]
;W[on]
(;B[so])
(;B[sp]
;W[pn]C[But white just connect his stones out and black ends
in failure again.]))
(;B[qn]C[This is the correct way to threaten the weakness
in white's shape]
(;W[pn]
;B[qo]
;W[ro]
;B[rn]
(;W[so]
;B[sn]C[If white goes this way he just gets captured.])
(;W[sn]
;B[sm]C[He is behind in the capturing race]))
(;W[qo]C[This looks stronger for white]
;B[pn]
;W[rn]C[White looks like he is escaping by linking up...]
;B[ro]
;W[so]
;B[sp]
;W[ro]
;B[rm]C[But black can just wrap the white stones into a ball
and capture them.])))
