(;AB[ka]AB[kb]AB[kc]AB[kd]AB[je]AB[ie]AB[he]AB[hd]AB[gd]AB[gc]AW[ja]AW[jb]AW[jc]AW[jd]AW[ke]AW[le]AW[me]AW[md]AW[mc]AW[mb]AW[ma]AW[hb]AW[jf]AW[if]AW[hf]AW[gf]AW[ff]AW[ee]AW[ed]AW[ec]AW[kg]AB[gb]AB[ga]AB[fc]AB[eb]AB[ea]AW[db]AW[cc]AW[bb]C[Black invaded White's moyo to deep. White to play. If you want to take liberties in the M column start at M16 and go upwards.]AP[goproblems]
(;W[ib];B[ha]
(;W[ld];B[ic]
(;W[lc];B[ia]
(;W[lb]C[Well done. The empty triangle is the only move to save the H18 stone without losing liberties, so you kill the left group as well.RIGHT])
(;W[la]C[NOTTHIS]))
(;W[lb]C[NOTTHIS])
(;W[la]C[NOTTHIS]))
(;W[hc];B[id]C[CHOICE])
(;W[lb]C[NOTTHIS])
(;W[la]C[NOTTHIS])
(;W[lc]C[NOTTHIS]))
(;W[ld];B[ib];W[lc];B[ic];W[lb];B[ha]C[You caught some stones but the left group is alive.])
(;W[hc];B[ib]
(;W[ha];B[id]C[CHOICE])
(;W[ia];B[ha]C[CHOICE])
(;W[ic];B[ha]C[CHOICE])
(;W[ld];B[id]
(;W[lc];B[ic]C[CHOICE])
(;W[ic];B[ha]C[CHOICE])))
(;W[ha];B[ib]
(;W[ic];B[hc]C[CHOICE])
(;W[hc];B[id]C[CHOICE])
(;W[ld];B[ic]C[CHOICE]))
(;W[ia];B[ic]C[CHOICE])
(;W[ic];B[hc]
(;W[ha];B[ib]C[CHOICE])
(;W[ld];B[id]C[CHOICE])
(;W[ia];B[id]C[CHOICE]))
(;W[la]C[FORCENOTTHIS])
(;W[lb]C[FORCENOTTHIS])
(;W[lc]C[FORCENOTTHIS]))