(;
AB[fc][cf][jj][ck][qn][eo][ro][eq][qq]
AW[nc][cd][pd][di][po][op][kq][pr]
PL[W]
TR[cf]
C[White's response to the marked play?

Source:
Go World #22, p. 57
1980 European Championship,
Commentary:  Sakai Masanori 4p
White:  Mattern (W. Germany)
Black:  Macfadyen (Great Britain)]
(;
W[ed]
C[In the game, White extends here, which gives Black too good of a reply.];
B[ef]
C[A bold and beautiful move.];
W[fd];B[gf]
C[Black creates an intimidating left side framework.  The game is still playable, but after this White falls behind trying too hard to directly address Black's framework.

White had a better initial response.]
)
    (;
    W[de]
    C[White should play this kosumi.];
    B[df]
    C[If Black pushes, ...];
    W[ef];B[eg];W[dg]
    C[... White can cut here to fight.];
    B[dh]
    C[For example, ...];
    W[eh]
    C[... White has this classic tesuji.];
    B[cg];W[fg];B[ci];W[dg];B[ch];W[ed]
    C[This result is excellent for White, because White's thickness nullifies Black's center stone.

Compare this result with the game line.]
    (;
    B[db]
    C[Next, if Black slides, ...];
    W[hc]
    C[... White counters here.]
    )
        (;
        B[ic]
        C[If Black forms a base, ...];
        W[ec]
        C[... White descends.]
        )
    )
)

