(;
AB[nc][pd][og][oh][pg][ph][nh][ni][nj][qh][qi][cj][pj][pk][pl][pm][ok][rk][nl][nm][jm][mm][mn][mo][rm][cn][en][ln][fo][go][jo][no][op][rp][pq]
AW[ec][of][pf][qf][ng][qg][rh][ri][rj][qj][mk][ml][nk][cl][kl][km][kn][ko][kp][ol][om][lm][fn][nn][pn][eo][lo][qo][cp][dp][fp][mp]
C[Black's response to the marked cut?

Source:
Go World #23, p. 57
French Championship game
Commentary:  Sakai Masanori 4P]
TR[eo]
(;
B[do]
C[In the game, Black misses a grand clear-cut opportunity with this atari.];
W[ep]
C[Now Black has a harder time pressing for a clear advantage.];
B[em];W[gn];B[ho];W[fl];B[gl];W[hm];B[im];W[hl]
C[After long complicated fighting, White goes on to win.]
)
    (;
    B[gp]
    C[For example, Black should block here.]
    (;
    W[dn]
    C[If White ataris here, ...];
    B[fq]
    C[... Black counter-ataris.];
    W[em];B[iq]
    C[Black has sente to settle here inside the middle of White's framework.  Black has a clear lead.

Note that if White now pincers the triangled stone, Black simply enters the top left corner.  White has scant territory, and White's lower middle group is weak.]
    TR[cj]
    )
        (;
        W[fq]
        C[If White defends by descending here, ...];
        B[do];W[ep];B[fm];W[gn];B[hn];W[gm];B[gl];W[hm];B[hl];W[im];B[il];W[in];B[jn];W[ho];B[io]
        C[... now Black can catch the cutting stones in a liberty shortage.]
        )
    )
)

