(;
AB[em][fm][gm][dn][in][io][ip][co][fp][bq][cq][hq][hr][ar][gr]
AW[fn][gn][eo][ho][dp][gp][gq][eq][fr]
C[Black plays.]
(;
B[dr]
C[Takes away a vital point, but fails.];
W[fo]
LB[hn:A][hp:B]
C[Black cannot make the inside eye false, and A and B are miai for the 2nd eye.];
B[fq];W[er]
)
    (;
    B[fq]
    C[The only move.]
    (;
    W[dr]
    C[The best defense.];
    B[fs];W[es]
    C[At least White has a ko for the life of the group.]
    )
        (;
        W[fo]
        C[A mistake.];
        B[er]
        C[Now Black can make the inside eye false.];
        W[fs];B[dr]
        )
        (;
        W[er]
        C[Protecting the inside eye this way is also a mistake.];
        B[hp]
        C[Black can ruin the 2nd eye in sente.]
        )
    )
)

