This problem was inspired by BartTM's comments about problem 8906.
No prisoners, 0.5 komi, (Its Black 19: White 19.5).
No unnecessary moves please. USE A4 TO PASS.
(;SZ[9]AW[ca]AW[da]AW[ea]AW[bb]AW[db]AW[cc]AW[ad]AW[bd]AW[ag]AW[bg]AW[cg]AW[dg]AW[fg]AW[eh]AW[fh]AW[hh]AW[ih]AB[fa]AB[eb]AB[fb]AB[dc]AB[fc]AB[cd]AB[dd]AB[fd]AB[ae]AB[be]AB[ce]AB[fe]AB[ef]AB[gf]AB[hf]AB[eg]AB[hg]AB[ig]C[White just passed, can black win? P to pass and end the game]AB[df]AW[gg]AW[bi]AB[de]AB[ff]LB[af:P]GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Japanese]KM[0.00]PW[Blanc]PB[Noir]TW[aa]TW[ba]TW[ab]TW[cb]TW[ac]TW[bc]TB[ga]TB[ha]TB[ia]TB[gb]TB[hb]TB[ib]TB[ec]TB[gc]TB[hc]TB[ic]TB[gd]TB[hd]TB[id]TB[ge]TB[he]TB[ie]TB[if]
(;B[ab]
(;W[bc];B[ba];W[aa]
(;B[af]
(;W[ba]C[Good. White had to fill at B9 to avoid the ko she couldn't win. The score is now Black 19: White 18.5RIGHT])
(;W[bf]C[RIGHT];B[ba]C[No ko threats];W[cf];B[cb]C[RIGHT]))
(;B[gi];W[ba]C[Black can't kill, you wasted a point and lost by half a point.]
(;B[dh];W[gh])
(;B[gh];W[fi]
(;B[dh];W[hi])
(;B[ii];W[hi])
(;B[hi];W[ii])))
(;B[bf]
(;W[ba]C[Good. White had to fill at B9 to avoid the ko she couldn't win. The score is now Black 19: White 18.5RIGHT])
(;W[af];B[ba]C[No ko threats];W[cf];B[cb]C[RIGHT]))
(;B[cf]
(;W[ba]C[Good. White had to fill at B9 to avoid the ko she couldn't win. The score is now Black 19: White 18.5RIGHT])
(;W[af];B[ba]C[No ko threats];W[bf];B[cb]C[RIGHT]))
(;B[dh];W[ba]C[Black can't kill, you wasted a point and lost by half a point.])
(;B[gh];W[ba];B[gi];W[fi]
(;B[hi];W[ii])
(;B[dh];W[hi]))
(;B[bh]C[Black can't kill, you wasted a point and lost by half a point.]))
(;W[af]
(;B[bc];W[ac];B[bc]C[RIGHT])
(;B[ba];W[aa])
(;B[bf]C[RIGHT]))
(;W[aa]
(;B[ba]C[No ko threats];W[af]
(;B[cb]C[RIGHT])
(;B[ac]C[RIGHT])
(;B[bc]C[RIGHT]))
(;B[af])))
(;B[ac];W[bc];B[ab];W[af]
(;B[ba];W[aa])
(;B[aa];W[ba]))
(;B[bc];W[ac])
(;B[aa];W[ab])
(;B[ba];W[aa])
(;B[dh];W[ab]C[You cant kill either group]
(;B[gi];W[gh];B[ei];W[ch])
(;B[ch];W[bh]))
(;B[gi];W[ab]
(;B[gh];W[fi];B[dh];W[hi])
(;B[fi];W[ei];B[hi];W[af]
(;B[ii];W[gh])
(;B[gh];W[ii])
(;B[dh];W[ch]
(;B[di];W[ci])
(;B[gh];W[ii]))))
(;B[cf]C[This move is unnecessary, filling dame will not create a ko threat at D2 and besides, you don't need one.]TR[dh])
(;B[bf]C[This move is unnecessary, filling dame will not create a ko threat at D2 and besides, you don't need one.]TR[dh])
(;B[af]C[No need to pass, black can win])
(;B[ai]AW[ia]C[This also used to be the pass button]TR[ia])
(;B[ee]C[This used to be the pass button]))