(;
AB[kk][il][ml][in][jn][ln][mn][ko][kp][kq][lq][jr]
AW[km][kn][jo][jp][jq][lo][lp][mp][mq][iq][ir][nq][oq]
C[Black plays.]
(;
B[kr]
C[Too slow.];
W[js];B[mr];W[ks];B[lr];W[nr]
C[Black loses the semeai.]
)
    (;
    B[mr]
    C[The standard tesuji that lets Black avoid an outright loss at the bottom.]
    (;
    W[ms]
    C[Best.  The other variations show inferior White defenses.

Congratulations to Kellin Pelrine, who pointed out that this nice edge tesuji gives White a better result than the original incorrect solution!];
    B[kl]
    C[For example, ...];
    W[lr];B[kr];W[ks]
    C[White has a ko, but at least Black takes 1st.]
    )
        (;
        W[nr];B[kl];W[lr];B[kr]
        )
        (;
        W[ls];B[lr];W[nr];B[ks]
        )
        (;
        W[ks];B[lr]
        )
        (;
        W[kr];B[lr];W[js];B[kl]
        )
    )
)

