(;
AB[br][dp][cq][fp][hs][hr][ir][iq][jq][ip][il][jl][hl][hj][gj][km][kn][ln][gi]
AW[bq][ij][ik][jk][js][jr][is][jp][bp][kp][kq][lr][ii][hi][kl][ll][lm][mm][cn][dl][dj][ch][en]
C[Black's best play?

Source:
    "Masterpieces of Handicap Go", Kato Masao 9p
    American Go Journal, Vol. 28, No. 3, p. 23]
(;
B[gn]
C[In the game, an 11 year old Kato mistakenly played here.];
W[cr]
C[Kato's teacher, Kada Katsuji 8p, punished his mistake with this cut.];
B[dr];W[cp]
C[Now White can reinforce with sente.];
B[cs];W[do]
C[White has another forcing move.];
B[ep]
C[And White has sente to play a big endgame move elsewhere.]
)
    (;
    B[bo]
    C[The correct endgame tesuji.]
    (;
    W[co]
    C[Forced];
    B[cp]
    C[Now Black threatens to capture 2 stones.];
    W[bn];B[aq]
    LB[cr:A]
    C[With this sente move, Black protects against the cut at A.];
    W[ao];B[gn]
    C[With sente Black can now extend to make a few points in the center without having to worry about White reducing the corner.]
    )
        (;
        W[cp]
        C[White can also try this approach.];
        B[co];W[dq];B[ap]
        (;
        W[do]
        C[White sacrifices the 3 stones to reduce Black's bottom area, but ...];
        B[aq];W[ep];B[cp];W[fq];B[fo];W[eo];B[gq];W[bn];B[fr];W[eq];B[dr]
        C[... although the shape is quite different, Black has about the same amount of territory.]
        )
            (;
            W[cr]
            C[Too greedy.];
            B[aq];W[cq];B[do]
            C[At worst, Black could even just connect here.  All of White's corner stones die.]
            )
        )
    )
)

