(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[ro][mp][np][op][pp][qp][rp][mq][mr][rr][ns][os][ps]AB[qm][rn][lo][mo][no][oo][po][qo][lp][lq][lr][nr][or][ls][ms]C[Does White need to defend the corner?]
(;B[pr]C[If black plays this way then he doesn't capture.]
;W[qs]
;B[qr]
;W[rs]
;B[rq]
;W[qq])
(;B[qs]C[Nor does this work.]
;W[pr]
;B[pq]
;W[qr])
(;B[qr]C[However black can play here]
(;W[pr]C[This clearly fails]
;B[pq])
(;W[qs]C[and this fails too.]
;B[rs]C[Black plays this throw-in]
;W[ss]
;B[pr]
;W[rs]
;B[rq]C[White runs out of liberties and gets captured.
Infact all the white stones are dead.

So yes White should defend.])
(;W[rs]C[If white doesn't defend, then when black attacks he should give up the edge stones and play here.]
;B[qs]
;W[qq]
;B[pr]
;W[sq]C[This way white gets two eyes for the rest of the group.])))
