(;
AB[bb][jb][kb][bc][ic][cd][dd][ed][fd][gd][hd][id]
AW[cb][hb][ib][cc][dc][ec][gc][hc]
C[Black plays.

Is the official solution wrong?!]
(;
B[fc]
C[This incorrect official solution only leads to a ko?];
W[fb]
(;
B[ca]
C[The official solution ...]
(;
W[ga];B[ea]
C[The official solution end here, supposedly with Black killing.  BUT ...];
W[da]
C[... White has this throw-in!]
(;
B[eb];W[fa]
C[White lives with most of the group.]
)
    (;
    B[db]
    C[If Black tries to kill the entire group, ...];
    W[eb]
    C[White lives outright.  White has 3 potential eyes, but Black can only destroy 1 of those.]
    )
)
    (;
    W[da]
    C[White does not have time to block here.];
    B[eb]
    (;
    W[ba];B[ia]
    (;
    W[ga];B[ja];W[ha];B[ea]
    C[White dies of a shortage of liberties.]
    )
        (;
        W[ha];B[fa]
        )
    )
        (;
        W[ga];B[ia];W[ba];B[ja];W[ha];B[ea]
        C[White dies of a shortage of liberties.]
        )
    )
)
    (;
    B[da];W[ga];B[eb];W[ia];B[fa]
    C[Black only has a ko that White takes 1st.]
    )
)
    (;
    B[fb]
    C[The correct killing move?];
    W[fc];B[ca]
    (;
    W[da];B[eb]
    (;
    W[fa];B[ea];W[ia];B[db]
    )
        (;
        W[ea];B[ia];W[ha];B[fa]
        )
    )
        (;
        W[fa]
        (;
        B[eb];W[gb];B[ia];W[ha];B[db]
        )
            (;
            B[ea]
            C[Fails];
            W[da];B[db];W[eb]
            C[White has a ko.]
            )
        )
        (;
        W[eb];B[da]
        )
        (;
        W[gb];B[ia]
        )
    )
    (;
    B[da]
    C[Fails];
    W[ca]
    (;
    B[fc];W[fb]
    (;
    B[eb];W[ga];B[ia];W[ea]
    C[Black only has a ko.]
    )
        (;
        B[ga]
        C[Even worse];
        W[ea];B[gb];W[db]
        C[White lives in sente with most of the group.]
        )
        (;
        B[ia]
        C[Worst];
        W[ea]
        C[All of White's stones live.]
        )
    )
        (;
        B[ia];W[fc]
        )
    )
)

