(;
AB[qd][pd][od][oe][nc][nf][ng][oh]
AW[ne][of][pe][qf][og][nh]
PL[W]
TR[oh]
C[White's best response to the marked cut?
(Assume that all ladders are favorable for White.)

Source:
    Go World #18, p. 37
    Advanced Tesuji Problems, #3]
(;
W[ni]
C[Extending here is the most obvious play.];
B[me]
C[Black then prevents the outside ladder.]
(;
W[ph]
C[White can catch the cutting stone in a ladder, but later Black can play a ladder breaker on the right side.

White has something better.]
)
    (;
    W[pi]
    LB[qg:A]
    C[White could also catch the cutting stone with this net, in order to avoid the problem with the previous variation.

But now Black has the aji of the contact play at A.  White still has something better than this variation.]
    )
)
    (;
    W[pi]
    C[The surprisingly correct play is here.]
    (;
    B[ph]
    C[If Black tries to escape here, ...];
    W[qh];B[oi];W[ni]
    C[... White can force here.];
    B[oj];W[mf]
    C[White captures 2 stones in a ladder.  Black cannot allow this result.]
    )
        (;
        B[me]
        C[If Black prevents the ladder, ...];
        W[oi]
        C[... White solidly captures the cutting stone.  Now White has no defects in his shape.]
        )
    )
)

