(;
AB[dc][cd][de][be][bf][ec][fc][fb][fa]
AW[eb][ea][da][db][cc][bc][bd][ad]
(;
B[cb]
C[The obvious move, but bad timing.]
(;
W[bb]
C[Maybe Black expects this inferior defense?];
B[ba]
C[Black kills the corner with a snapback.]
)
    (;
    W[ba]
    C[White can dodge to here!]
    (;
    B[bb];W[ab];B[ca];W[db]
    C[White salvages a ko.]
    )
        (;
        B[ca]
        C[Even worse.];
        W[bb];B[ab];W[db]
        C[White lives.]
        )
    )
)
    (;
    B[bb]
    C[A big mistake.  Now Black doesn't even have a ko.];
    W[cb]
    C[White instantly lives with a seki.]
    )
    (;
    B[ba]
    C[Correct.  The only move.];
    W[bb]
    (;
    B[ab]
    C[Bad timing.]
    (;
    W[ca];B[cb];W[db]
    (;
    B[da]
    C[White takes the ko 1st.]
    )
        (;
        B[ca];W[da];B[eb];W[aa];B[ba];W[ca];B[ea]
        C[White takes the ko 1st.]
        )
    )
        (;
        W[ac]
        C[Inferior];
        B[cb]
        C[For example ...];
        W[aa];B[ca];W[db]
        C[Black takes the ko 1st.]
        )
    )
        (;
        B[ca]
        C[The correct follow up.];
        W[cb];B[ab];W[aa];B[ba]
        C[Black forces a bent four.  White dies!]
        )
    )
)

