This is problem #6 from chapter 10 entitled "Sacrifice to Gain Tempo".
(;AB[cq]AB[dq]AB[cp]AB[co]AB[cn]AB[dm]AB[dl]AB[dk]AB[fm]AB[gn]AB[fo]AB[er]AB[fr]AW[eq]AW[fq]AW[gq]AW[dp]AW[do]AW[dn]AW[en]AW[fn]AW[gm]AW[iq]AW[cm]AW[cl]AW[ck]AW[cj]TR[gm]C[Capture the marked stone]AW[jj]AP[goproblems]
(;B[ep];W[go]
(;B[hn];W[fp]
(;B[hl]TR[gm]LB[gl:a]LB[em:b]C[success! White a is answered by black bRIGHT])
(;B[em];W[eo];B[hl]C[success! the white stone cannot escape nowRIGHT]TR[gm])
(;B[ho];W[eo];B[hl];W[gl]C[Close but you destroyed your opportunity to force white a couple moves back];B[gk];W[fl];B[em];W[hm];B[im];W[hk];B[il];W[fk];B[gj]C[it's not looking too good for black... try again])
(;B[gl]C[Close, but the ladder fails... try again])
(;B[hm];W[gl]C[Close, but now you need to keep the white stone contained]))
(;B[em];W[hn]))
(;B[gl];W[hm]C[Attacking the white stone directly is not going to work... You need something to keep white busy while you set up for the attack])
(;B[hm];W[gl]C[Attacking the white stone directly is not going to work... You need something to keep white busy while you set up for the attack])
(;B[fl];W[hm])
(;B[hn];W[fl]
(;B[em];W[ep]
(;B[hm];W[gl]C[Attacking the white stone directly is not going to work... You need something to keep white busy while you set up for the attack])
(;B[gl];W[hm]
(;B[hl];W[im]C[Attacking the white stone directly is not going to work... You need something to keep white busy while you set up for the attack])
(;B[im];W[hl]C[Attacking the white stone directly is not going to work... You need something to keep white busy while you set up for the attack])))
(;B[gl];W[em])
(;B[hm];W[gl]))
(;B[hl];W[hm];B[im];W[gl];B[gk];W[fl]
(;B[em];W[hk]
(;B[il];W[fk];B[gj];W[fj]LB[dj:a]LB[gi:b]C[black has to prevent white from playing one of a or b (BTW: The net was a good idea at the start but the timing is all wrong. You need to do something else first)])
(;B[hj];W[il]C[there has to be a better way... try again]))
(;B[fk];W[il]
(;B[hk];W[in];B[jm];W[go]C[The net was a good idea at the start but the timing is all wrong. You need to do something else first])
(;B[hn];W[hk];B[el];W[em]C[The net was a good idea at the start but the timing is all wrong. You need to do something else first])))
(;B[fp];W[go];B[hn];W[gp];B[hl];W[gl];B[gk];W[hm];B[im];W[fl];B[em];W[hk];B[il];W[fk];B[gj];W[fj]LB[dj:a]LB[gi:b]C[black has to prevent white a or b... try again (BTW: The net was a good idea at the start but the timing is all wrong. You need to do something else first)])
(;B[em]
(;W[ep]
(;B[hm];W[gl])
(;B[hn];W[gl]))
(;W[fp];B[eo];W[ep];B[go];W[hm])))