(;
AB[cp][ep][jq][jo][je][jd][jc][od][oe][qd][qc][ed][fc]
AW[dc][de][cf][fe][hf][id][ck][pc][pf][qi][pq][qn][mq]
C[Should Black play at A, B, C, or D?

Source
    Go World #14, p. 59
    "How Would You Play Here?", Miyamoto Naoki 9P
    1949 game, Kubouchi 6P (Black) vs. Go Seigen 8P]
LB[cm:A][ek:B][pl:C][hc:D]
(;
B[ek]
C[Correct.  This move expands the lower framework, while making White's entire left side position thin.  A perfect dual-purpose move.

This point would also have been a good point for White.];
W[ho]
C[Rather than respond and be forced, Go Seigen probed twice in the lower left, and ...];
B[hq];W[cq];B[bo];W[ln]
C[... then switched to the lower right here.];
B[pj]
C[Now Kubouchi 6P can shoulder hit here with perfect timing.  The game is going well for Black.

Black eventually won by 4 points.

The next few moves show a bit more of how the game developed.];
W[pi];B[oj];W[oi];B[nj];W[rk];B[lj]
C[Black keeps the game simple.];
W[gk];B[on];W[ol];B[op];W[pp];B[pl];W[pm];B[om]
(;
W[pk];B[nl];W[ql];B[mn]
C[After linking together here, Black has a very easy position.]
)
    (;
    W[nl]
    C[White would like to play here, but ...];
    B[ql]
    C[... White cannot tolerate Black descending here.]
    )
)
    (;
    B[cm]
    C[An 80% move.  Black strengthens the corner, aiming for profit, but ...];
    W[ek]
    C[... White takes the biggest point.  Reducing the upper left side will be difficult for Black.]
    )
    (;
    B[pl]
    C[Another 80% move.  Black reduces the right side framework, but this move has little connection with any of Black's frameworks.]
    )
    (;
    B[hc]
    C[Locally a big move, but globally short-sighted.

Note though that even if White plays here first, Black still has some corner aji.  See the following sequence.];
    AE[hc]
    W[hc]
    C[Assume that White tries to cut off the 2 stones.];
    B[dd]
    C[Black has the following sequence.];
    W[cd];B[cc];W[cb];B[bc];W[eb];B[fb]
    C[Black can descend here in sente.];
    W[bb]
    C[White must come back to defend the corner, but ...];
    B[hb]
    LB[dg:A][di:B]
    TR[hc]
    C[... Black links up anyway.

In addition, now Black A is sente, so Black can aim at an invasion at B.

With such possibilities, White is unlikely to be in a rush to play the marked stone.]
    )
)

