(;
AB[qd][od][qg][pq][op][qk]
AW[qi][pm][qo][pj]
C[Black's response to the marked stone?

Source:
    American Go Journal, Fall 1988, Vol. 22, No. 4, p. 29
    Keshi and Uchikomi, Kaoru Iwamoto 9 dan]
TR[pj];
B[pk];W[ok]
(;
B[ri];W[rh];B[rj];W[qh];B[rg]
(;
W[ol];B[sh];W[ni]
C[Black's invading stones connect out in sente, but White gains outside influence.]
)
    (;
    W[sh]
    C[Stopping Black from connecting out is bad.];
    B[rm];W[qm];B[rl];W[rn]
    C[Blocking here does not kill Black.];
    B[ol];W[pl]
    (;
    B[oj]
    C[And if the ladder in this line is not good for White, White collapses.];
    W[nk];B[pi];W[qj];B[ph];W[oi];B[nj];W[mj];B[ni];W[oh];B[pg];W[nh]
    C[This ladder must work for White.]
    )
        (;
        B[si]
        C[But even if the ladder is good for White, at worst, Black can live easily.];
        W[sk]
        C[If White persists ...];
        B[oj];W[nk];B[pi];W[qj];B[ph]
        C[... White collapses.]
        )
    )
)
    (;
    B[ol]
    C[Bad timing.];
    W[pl]
    C[Black loses a critical liberty.];
    B[ri];W[qj]
    C[White captures the invading stones.]
    )
)

