(;
AB[rc][qc][pc][oc][nb][pd][qe][re][sd][jd][dc][de][ce][ec][cj][eq][dq][cp][cn][dl][fm][rq][qo][qn][rm][rl][rk][ql][en][dm][ck][di][ei][fh][gh][gf][ff][fj]
AW[rf][qf][pe][od][nc][mc][oe][qk][rj][pj][pl][pm][qm][pn][op][pq][jp][jm][fq][fp][ep][ej][eg][cg][db][ie][hg][hh][fi][gi][eh][dk][el][em][fn][fl]
TR[fl][fj]
C[Black plays.

This problem is a follow up to last week's problem after Black incorrectly made the marked exchange.  Black now has a harder task to reduce White's moyo.  How?

Source:
    American Go Journal, Summer 1990, Vol. 24, No. 3, p. 25
    "Jim's Journal", James Kerwin 1p
    The game is from 2-dan players at a US Go Congress.];
B[gk]
C[A nice tesuji that threatens both the upper and lower stones.];
W[gj];B[fk]
(;
W[hk]
C[White's best response.];
B[dj];W[gl];B[ek];W[hl]
C[White must protect here to prevent Black from breaching the left wall with simple atari plays.];
B[je]
C[Now Black can use sente to reduce from another direction.]
)
    (;
    W[ek]
    C[Too greedy.  White cannot connect to save the left 2 stones.];
    B[hk]
    C[After Black extends, White has no response.];
    W[ij]
    C[For example, if White defends from above, ...];
    B[gm];W[gl];B[hl]
    C[... White collapses after Black captures the 7 stones.]
    )
)

