(;
AB[pd][ql][om][po][pp][pq][jp][fq]
AW[dd][cn][qn][rn][dp][qp][qq][hq]
TR[hq]
C[Black's response to the marked play?

Source:
     American Go Journal, v35 #4, pp. 23-24
     Originally from "A Middle Game Joseki", Baduk Monthly.]
(;
B[fo]
C[When White has this strong lower left corner, Black's jump toward the center here is unthinkable.];
W[ho];B[fm];W[hm]
)
    (;
    B[jq]
    C[What about Black's descent?];
    W[fp]
    C[White will attach on the top here.];
    B[eq];W[dq];B[ep];W[eo];B[gp];W[fo];B[gq];W[go]
    C[White settles his shape.];
    B[hp]
    C[You might argue that Black makes a lot of territory by swallowing the one stone, but Black is overconcentrated.  But White gains significant left side influence and has sente.  The position looks favorable for White.]
    )
    (;
    B[dq]
    C[Black's attachment might seem like a leaning attack, indirectly aiming at A against the marked stone, but the result does not turn out well.]
    TR[hq]
    LB[hp:A];
    W[cq]
    (;
    B[ep];W[dr]
    C[White's atari creates a dilemma for Black.  Now Black does not want to either connect to make an empty triangle or start a ko.]
    )
        (;
        B[hp]
        C[Black can try to develop territory, but ...];
        W[eq];B[fp];W[fr];B[gr];W[er]
        C[... White is satisfied to make a solid corner territory.];
        B[gq]
        TR[kn][qr][gs]
        C[Later, White has the 3 marked sente plays to reduce Black's territory.  So Black's lower territory is less than 30 points, while White has more than 20 points in the lower left and sente.]
        )
        (;
        B[cr]
        C[Another possibility, but ...];
        W[eq];B[dr];W[fp];B[er];W[ep]
        C[... White can respond simply.];
        B[cp];W[bq];B[bp];W[co];B[br];W[dj]
        C[White clearly benefits from the exchanges in the lower left.]
        )
    )
    (;
    B[hp]
    C[This attachment is best for Black, and the following standard sequence is the best for both sides.];
    W[iq];B[ip];W[jq];B[kq];W[kr];B[gq];W[lq];B[kp];W[mr];B[hr];W[is];B[cq]
    C[White lives on the lower side, reducing Black's territory.  But Black has center thickness as compensation.  Black also has time to invade the lower left corner.]
    )
)

