(;
AB[nc][nd][qc][pd]
AW[ic][lc][pc][qd][qf]
LB[qd:A][qc:B][pc:C]
C[White's marked combination is not really a trick sequence, but Black still has to be careful.

How should Black respond to avoid giving White an unfair advantage?

Source:
    Go World #21, pp. 39-40
    "Some Popular Trick Moves", Kato Masao 9p]
(;
B[pb]
C[Dubious.];
W[rc]
LB[pe:A]
C[(Note:  Depending on the overall position, White might atari at A instead.)];
B[oc];W[re]
TR[oc]
C[With the marked stone, Black is over-concentrated and has made bad shape empty triangle.]
)
    (;
    B[rc]
    C[Even the proverb, "extend after crosscut" is a mistake here.];
    W[pe];B[od];W[rd];B[pb]
    C[Again, Black makes an empty triangle.]
    )
    (;
    B[rd]
    C[Correct 1st move.];
    W[qe]
    C[But can you now spot Black's next move?];
    B[qb]
    C[Tesuji.  Now Black's marked stone does not become over-concentrated.]
    TR[nc];
    W[od]
    C[For example ...];
    B[oe]
    C[Important.];
    W[pe];B[pb];W[ne]
    C[Black does not have to worry about this cut.];
    B[of]
    C[Black is OK -- White's stones to the right are eye-less.]
    )
)

