(;
C[White plays.

Source:
    Go World #38, p. 42
    Basic Fighting Techniques]
AB[ra][rb][qb][qc][pc][od][oe][of][qe][re][rg]
AW[oc][nc][pb][md][kd][qd][pd][rd][rc][sb]
(;
W[pa]
C[At first glance, White seems to have this trivial way to kill Black.];
B[ob]
C[But Black gives White this nasty surprise.  This well-known, but surprising, tesuji occurs in numerous situations.];
W[nb]
C[White, who is in a shortage of liberties, has to make 2 moves to capture Black's single stone throw-in.];
B[sd]
C[Black can use that extra move to win the semeai.];
W[oa];B[pe]
)
    (;
    W[oa]
    C[But White has a resource that Black has no answer for.];
    B[sd];W[qa]
    C[Black cannot stop White's throw in to force a ko.]
    )
)

