(;
AB[cd][ec][fb][gb][ic][oe][od][qe][qd][qc][qb]
AW[hc][gc][hb][id][he][kc][le][ne][nd][oc][pc][pb]
C[Black's best endgame sequence?

Source:  based on a problem from the classic Gokyo Seimyo collection.]
(;
B[pa]
C[Bad timing.];
W[oa];B[qa];W[nb]
C[White must defend to prevent Black from taking this point.  This move performs another useful function that becomes apparent in the following sequence.];
B[ha];W[ia];B[ga]
C[This connection is not sente!  White can tenuki.];
B[ib]
C[For example ...];
W[ja];B[jb];W[ka];B[kb];W[la];B[lb];W[ma];B[mb];W[na];B[mc];W[nc]
C[Looks scary, but Black has nothing.]
)
    (;
    B[ha]
    C[Playing on this side first is no better.];
    W[ia]
    C[After White blocks here, ...];
    B[ga];W[nb]
    C[... White can defend both the left and right sente hane plays with this one move.]
    )
    (;
    B[nb]
    C[Best endgame play.]
    (;
    W[nc]
    C[White has to defend submissively.];
    B[ha];W[ia];B[ga];W[ib]
    C[Black hanes on the left in sente.];
    B[pa];W[oa];B[qa];W[ob]
    C[And Black hanes on the right in sente for maximum benefit.]
    )
        (;
        W[pa]
        C[An overplay.];
        B[nc]
        C[White has a big problem.];
        W[mc]
        C[For example ...];
        B[qa];W[mb];B[oa]
        )
    )
)

