(;
AB[ma][mb][mc][qb][qc][qd][qe][nd][ne][nf][of][pf][rf][rg]
AW[lb][lc][ld][nb][nc][jc][pc][md][od][oe][pe][lf][qf][qg][qh][mg][nh][oh][rh]
C[Black plays.

Source:
Test Your Rating
Go World #27, p. 35,  Spring 1982]
(;
B[oc]
C[Throwing in here reduces White's liberties and is often the move to win a liberty race.

However, ...];
W[ob]
(;
B[pd];W[oc]
C[... White still has too many liberties.  Black loses all the outside stones.]
)
    (;
    B[oa]
    C[Trying to run out now doesn't work either.];
    W[la]
    C[White captures the outside stones again.]
    )
)
    (;
    B[pb]
    C[Pushing in is too slow.];
    W[oc]
    C[White calmly connects to win the semeai.]
    )
    (;
    B[ob]
    C[Also fails.];
    W[oc]
    C[Similar to the previous variation.]
    )
    (;
    B[oa]
    C[The key move.  Black simultaneously threatens to link up or catch White in a liberty shortage.]
    (;
    W[na];B[oc]
    C[Now the throw-in works.];
    W[ob]
    C[If White tries to save everything, ...];
    B[pd]
    C[... Black captures some stones to save the 5 stones below.]
    )
        (;
        W[la]
        C[Even worse.];
        B[na]
        C[Black links up to capture the 6 inside stones.]
        )
    )
)

