(;
AB[pd][pf][pj][pp][cf][bf][ef][di]
AW[dd][dp][jd][nc][ch][ce][fc]
TR[ce][bf]
PL[W]
C[White's response after the marked exchange?

Source:
    American Go Journal, Vol. 33, No. 3, p. 28
    Go Seigen, "Way to Play for the 21st Century"]
(;
W[ci]
C[Usually White follows this sequence.];
B[dj];W[dh];B[eh];W[cj];B[dk];W[cl]
C[Black makes influence, while White makes territory.  Now the question is how both sides follow up to make use of their positions in light of the rest of the board.];
B[ed]
C[For example, one possible sequence follows.];
W[ec];B[cc];W[dc];B[cd];W[de];B[be]
)
    (;
    W[dh]
    C[But what if White changes the move order by pushing up first?];
    B[ci]
    C[White must be ready for Black to block here, instead of transposing back to the main line.];
    W[eh]
    C[If White pushes out ahead, ...];
    B[bh]
    C[... Black can connect underneath.];
    W[df];B[dg];W[de];B[cg];W[eg]
    C[Some players might be worried about White's cut here, but Black should welcome the cut.];
    B[ei];W[ff];B[cm]
    C[Black extends to protect the left side, but also leaves behind a formidable threat.];
    W[]
    C[If White ignores the top, can you spot Black threat?];
    B[kd]
    C[This attachment is Black's threat.];
    W[kc];B[lc];W[ld];B[ke];W[lb]
    C[After White's standard response to Black's attachment, ...];
    B[fh]
    C[... Black can unleash this great move.];
    W[fg]
    C[After White connects ...];
    B[jc]
    C[... the situation worsens for White.];
    W[mc];B[kb];W[lc];B[id]
    C[This ladder does not end well for White.];
    W[je];B[jf];W[ie];B[he];W[if];B[ig];W[hf];B[gf];W[hg]
    C[Black's ladder doesn't work, but ...];
    B[gg]
    C[... Black has this double atari.]
    )
)

