(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play and capture in the corner]
AW[ql][pm][qn][qo][rp][mq][nq][oq][rq][pr][qr]AB[nn][pn][po][ro][lp][np][pp][qp][pq][qq][or]
(;B[rr]C[Black should start with the 2-2 point.]
(;W[sr]
(;B[rs]C[When Black adds the second stone, it is self-atari for White on both sides.]
;W[rn]C[White can save the edge]
;B[ps]C[Black captures at the bottom])
(;B[rn]C[However Black can play this atari.]
(;W[qm]C[If White connects...]
;B[rs]C[...Black still play this as before...]
(;W[sq]C[...white can try connecting.]
(;B[sn]C[This sets up a ko where black has to find the first threat.]
;W[rm]
;B[sp]
;W[so])
(;B[sp]C[This way white has to find the first threat.]
;W[so]
;B[sn]
;W[rm]
;B[sp]C[White risks losing everything.]))
(;W[nr]C[White should capture the bottom.]
;B[sp]))
(;W[rs]C[However White can capture at the bottom instead.]
;B[qm])))
(;W[rs]
;B[sr]
;W[qs]C[If White protects the bottom this way. ]
(;B[sp]
;W[rn]
;B[sq]
;W[nr]C[White gets shape on the side and the bottom.])
(;B[rn]C[This now makes the black side bigger]
;W[qm]C[White should probably not connect...]
;B[sp]C[... as this is unnecessary as the two white stones cannot escape. ])))
(;B[rn]C[Should black play the atari here first?]
(;W[qm]C[If White connects...]
;B[rr]C[...then black plays the 2-2 point like before.]
(;W[sr]
;B[rs]
;W[sq]C[If White connects here...]
;B[sp]C[.. black can set up a ko shape.]
;W[so]
;B[sn]
;W[rm]
;B[sp]
;W[nr]C[White has no local ko threat.]
;B[ss])
(;W[rs]C[To avoid the ko white might play from this side and
elect to keep the bottom.]
;B[sr]
;W[qs]
;B[sp]C[This move is unnecessary as the two white stones cannot escape.]))
(;W[rr]C[However this gives White the chance to protect the corner.]
;B[qm])))
