(;
PL[W]
AB[rp][qk][qn][ip][dp][cq][dn][dj][df][dd][cc][jd]
AW[dc][fc][fe][pd][pp][qq][np][ir][fq][dr][fo]
C[Play through the variations to see Kato's commentary on this game between 2 kyu players.

Source:
    "Correcting the Mistake", Kato Masao 9P
    Go World, Vol. 13, pp. 59-60];
W[cb]
TR[fe]
C[Sometimes this hane is a tesuji.  But here the hane is a mistake that is inconsistent with the marked play.]
(;
B[bb]
C[Black's double hane looks stylish, but is also incorrect.]
(;
W[cd]
C[White makes another mistake.];
B[bc];W[de];B[ed];W[ee];B[ce]
LB[fd:A][cf:B]
C[Only now does White see a big problem.  White needs to play both A and B.]
)
    (;
    W[eb]
    C[This odd-looking diagonal connection is correct.];
    B[ca]
    C[White was worried about this atari.  If White starts a ko or connects, then White would be forced.  But ...];
    W[cd]
    C[... White's counter-atari works well.];
    B[db];W[de]
    (;
    B[ec];W[ed]
    C[White has the nice outside forcing move here.];
    B[dc];W[ce]
    C[After White connects here, the result is a rather good one for White.]
    )
        (;
        B[ed]
        C[No better.];
        W[ee]
        C[White simply connects.]
        )
    )
)
    (;
    B[ec]
    C[Black should have made the obvious atari here, and then ...];
    W[db]
    (;
    B[ed]
    C[... simply connect.];
    W[eb];B[fd]
    C[White cannot prevent Black from pushing through.]
    (;
    W[gc];B[gd]
    C[Black has a strong, easy-to-play position.]
    )
        (;
        W[gd]
        C[The double hane is no better.];
        B[gc]
        C[One possible sequence follows.];
        W[fb];B[hc];W[cd];B[ce];W[bc];B[ge]
        C[Black is clearly superior.]
        )
    )
        (;
        B[eb]
        C[Black must watch out not to push through here.];
        W[ed];B[fb];W[gc];B[gb];W[hb];B[hc];W[ib]
        C[Black collapses.]
        )
    )
)

