(;
AB[nd][pd][de][df][qe][cf][dj][pj][cn][pp]
AW[dc][fc][cd][ce][pf][qf][rj][dp][fp][jp]
C[Black's response to the marked play?

Source:
    American Go Journal V.34 No.3
    "What's Wrong With That Move?", Nakayama Noriyuki]
TR[rj]
(;
B[qk]
C[A mistake in thinking.];
W[rk];B[ql]
C[Normally, making White crawl on the 2nd line would be good for Black, but ...];
W[rl];B[qm];W[qh]
C[... White settles painlessly within Black's sphere of influence.  Also, White's marked stone erases much of the influence from Black's right side wall.]
TR[jp]
)
    (;
    B[rk]
    C[Black can avoid the previous timid variation, but this contact play is a little reckless.];
    W[qk]
    C[Fighting spirit.];
    B[qj];W[rl];B[ri];W[sk];B[qh];W[nq]
    C[Now White uses sente to approach the lower right.

White has destroyed the powerful influence of Black's initial 3 star point formation.

And later, White's 2 stones may be able to cause trouble by running out at A.]
    LB[nf:A]
    )
    (;
    B[qi]
    C[Black has other responses, but in this overall position, this diagonal move is the strongest measure.

For reference, various possible variations follow.];
    W[ri];B[rh]
    C[The key move.];
    W[qh]
    (;
    B[rg];W[rf]
    C[Allowing Black to connect would be too good for Black.];
    B[qg]
    (;
    W[ph];B[pg];W[pi]
    C[And now Black has to be careful.  Do you see the correct response?]
    (;
    B[oi]
    C[Correct.];
    W[oh];B[og];W[nh];B[qj]
    C[Black carries forth prospects for winning.]
    )
        (;
        B[og]
        C[Black captures the 3 stones above, but ...];
        W[oj]
        C[... Black has no prospects in the lower right side.]
        )
    )
        (;
        W[sh]
        C[White can connect underneath.];
        B[pg];W[sg];B[og];W[ql]
        C[White can catch his breath.  Black has sente.]
        )
    )
        (;
        B[qg]
        C[Also possible, but ...];
        W[rg];B[ph];W[sh]
        C[This early in the game, Black may not want to fight a ko.]
        )
    )
)

