White to play. Check the variations if you do not get it right.
(;AB[nq]AB[pq]AB[qp]AB[qo]AW[dp]AB[fc]AW[dd]AW[cf]AW[po]AW[qn]AW[pm]AB[qd]AW[qi]AB[oc]AB[jd]LB[fq:A]LB[jq:B]LB[qf:C]LB[db:D]LB[dn:E]LB[hc:F]LB[dj:G]C[FORCE]AP[goproblems]
(;W[qf]C[This secures white's group. RIGHT])
(;W[jq];B[qg]C[Because black's O3 group is solid so this area is not interesting. Also white has a weakness in R8.];W[cn];B[ql]
(;W[pk];B[rn];W[rm];B[qm];W[pn];B[rl])
(;W[rm]
(;B[pj];W[qj];B[qk];W[rk];B[rl];W[sl];B[rj];W[sk];B[pi];W[ri];B[qh];W[rh];B[rg];W[ol])
(;B[rj];W[pk]))
(;W[rn];B[pk]))
(;W[fq])
(;W[dn])
(;W[dj])
(;W[db])
(;W[hc]))
