(;
AB[pc][pd][ld][nd][me][oe][nf][pi][qj][rj][ok][ol][pk][ql][rm][po][qo][jp][mp][mq][fq][pq][qq][dr]
AW[nc][dd][kd][md][od][pj][qk][rk][pl][pm][pn][rl][cn][nn][qn][rn][ro][rp][dp][ip][kp][jq][nq]
PL[W]
C[White's response to the marked play?

Source:
    "Tesuji in an Actual Game" (originally from Weichi World)
    Duan Rong 7P
    American Go Journal, Vol. 36, No. 2, pp. 37-38]
TR[mq]
(;
W[np]
C[Trying to split Black apart here doesn't work.

What can Black do?];
B[nr]
C[With the following tesuji sequence, Black connects.];
W[or];B[oq];W[mr];B[no];W[ns];B[op];W[nr];B[mn]
)
    (;
    W[mr]
    C[In the game, White correctly played this hane.

Now how does Black respond?]
    (;
    B[np]
    C[In this speed game, Black mistakenly made this natural looking move.];
    W[nr]
    C[With this game move, White connects the lower stones.];
    B[mn];W[nm];B[mo]
    C[Black must come back here to end up with bad shape (an empty triangle).];
    W[op];B[oo];W[oq];B[no]
    )
        (;
        B[no]
        C[Instead, Black should have made this kosumi.];
        W[lr]
        C[After White connects the lower stones, ...];
        B[mn]
        C[... Black can hane here with good shape.]
        )
    )
)

