(;
AB[pd][ce][eo][qo][qp][eq][nq][pq]
AW[dc][qi][pm][dn][qn][po][cp][gp]
TR[dn]
C[Black's response to the marked play?

Source:
"The Great Joseki Debate"
Hunda Kunihisa 9P
Go World #26, pp. 29-33,  Winter 1981]
(;
B[dl]
C[The correct move and direction.

Black's move here not only blocks White's extension up the left side, but also works well with the marked top left stone.

Note also that Black can press White down at A at any time, which improves the left side even more.]
TR[ce]
LB[ed:];
W[en]
C[White pushes up here to keep Black from taking this point.];
B[fo];W[fm]
C[More joseki moves follow.];
B[cq];W[bq];B[dp];W[co];B[cr]
C[Black has a solid lower left shape, and a flexible left side.  The following variations show a couple possibilities.]
(;
W[ed]
C[White will probably play here next.];
B[ch]
C[But Black will make a firm foothold on the left.];
W[nc];B[qg]
)
    (;
    W[dh]
    C[If White pincers, ...];
    B[ed]
    C[... Black keeps play simple by pressing down.];
    W[dd];B[de];W[ee];B[dg];W[fe];B[eg];W[gc];B[dj]
    C[Black has an easy game, and can still pressure White's lower left. ]
    )
)
    (;
    B[ip]
    C[Pincering might look promising, but ...];
    W[gn]
    C[... after White jumps out, ...];
    B[gq]
    C[... Black will cross under here.  One sequence follows.];
    W[fp];B[fq];W[ep];B[dq];W[ci]
    C[White occupies an ideal point to have a favorable game.]
    )
    (;
    B[go]
    C[Black might try this attachment, another joseki, but ...];
    W[ho];B[gn];W[dl]
    C[... White will turn away from the lower side joseki to extend here.];
    B[hp]
    C[Athough cutting here makes Black very thick locally, ...];
    W[ch]
    C[... this pincer gives White the initiative.

Black is dissatisfied, because his thickness  is facing the lower side.]
    )
)

