Black says the corner is seki, you say it's dead. Since Black has no ko threats, you agree to capture the group. Don't waste time on eternal life or filling dame, just focus on the kill.
(;SZ[9]AB[hc]AB[gg]AB[ha]AB[hb]AB[gc]AB[fc]AB[ed]AB[ee]AB[ef]AB[eg]AB[eh]AB[ei]AB[da]AB[db]AB[cb]AB[bb]AB[bc]AB[bd]AB[ad]AB[fd]AW[df]AW[dg]AW[dh]AW[di]AW[cf]AW[ga]AW[gb]AW[fb]AW[ec]AW[ea]AW[eb]AW[dc]AW[cc]AW[cd]AW[ce]AW[be]AW[ae]AW[ba]AW[ab]AW[bg]GM[1]FF[4]AP[glGo:1.2-Beta2]ST[1]KM[6.5]PW[White]PB[Black]RE[W+10.5]DT[2005-05-20]AE[af]AE[bf]AE[ag]AE[cg]AE[ch]
(;W[aa];B[dd]C[In a real game, Black would pass here instead of filling dame.]
(;W[ac];B[ca]C[Now we're at the actual bent four in the corner stage. Go ahead and complete the capture, which is easy since Black has no ko threats.]
(;W[ab];B[aa];W[ba];B[de]C[Black has no ko threats, so must pass again.]
(;W[ac]C[RIGHT])
(;W[aa];B[ac];W[aa]C[RIGHT]))
(;W[aa];B[ab])
(;W[ac];B[ab])
(;W[ba];B[ab]))
(;W[ca];B[ac]C[Now we're at the actual bent four in the corner stage. Go ahead and complete the capture, which is easy since Black has no ko threats.]
(;W[ba];B[aa];W[ab];B[de]C[Black has no ko threats, so must pass again.]
(;W[ca]C[RIGHT])
(;W[aa];B[ca];W[aa]C[RIGHT]))
(;W[aa];B[ba])
(;W[ab];B[ba])
(;W[ca];B[ba])))
(;W[ac];B[aa];W[ab]C[All you've accomplished here is giving Black an extra prisoner.])
(;W[ca];B[aa];W[ba]C[All you've accomplished here is giving Black an extra prisoner.])
(;W[dd]C[NOTTHIS])
(;W[de]C[NOTTHIS]))