(;
AB[ba][bb][bc][ad][cd][ce][de][ee][fe][ec][fc][gc][ic]
AW[ca][db][eb][dc][cc][dd][bd][be][bf][cf][df][ef]
C[Black plays.

Source:
    Korean problem set pamphlet]
(;
B[ea]
C[The only move!]
(;
W[fb];B[gb];W[fa];B[ga];W[ab];B[cb];W[ac];B[da];W[ca];B[da]
C[With this beautiful sequence of 3 captures in a row on the same set of points, Black easily wins the semeai.]
)
    (;
    W[ab]
    C[Starting from the left gives Black a simple winning semeai.];
    B[fb]
    C[Now Black only needs to fill liberties from the right side to win.];
    W[ac];B[ed];W[ae];B[fa]
    )
)
    (;
    B[fb]
    C[The obvious way to reduce White's liberties here doesn't work.];
    W[ea]
    C[White creates half an eye that forces Black to eventually approach from the left.];
    B[fa];W[ab]
    (;
    B[cb];W[ac]
    C[White has a direct ko.  But Black can do better.]
    )
        (;
        B[ac]
        C[If Black cannot fight the ko in the previous variation, ...];
        W[ae];B[ed]
        C[... Black has this gote seki.  But Black can do better.]
        )
    )
    (;
    B[ac]
    C[Making an eye is too slow.];
    W[ae]
    C[White wins this trivial semeai by 1 move.]
    )
)

