(;
AB[sq][rq][qq][qp][qr][pp][op][np][lr][nq][mq]
AW[rr][qs][rs][ss][pr][pq][oq][nr][mr][kr][kq][qn][ro][on][lp][mo][iq]
C[Black plays.]
(;
B[ns]
C[An amazing tesuji, and the only way to expose White's liberty shortage!]
(;
W[lq];B[or]
C[Another counter-intuitive throw-in!]
(;
W[os];B[sr];W[ms];B[ps]
C[The crucial idea:  Black captures the corner stones in sente.];
W[qs];B[rs]
C[Black lives.]
)
    (;
    W[ps];B[sr]
    C[Snapback.]
    )
)
    (;
    W[or];B[lq];W[ls];B[ms]
    C[Now Black has this simple throw-in to prevent White from wriggling out of a liberty shortage.];
    W[ks]
    C[For example ...];
    B[sr];W[os];B[ms];W[ns];B[ps];W[qs];B[rs]
    )
    (;
    W[ms];B[os]
    (;
    W[lq];B[sr];W[or];B[ps]
    C[Again Black captures with atari to live.]
    )
        (;
        W[or]
        C[Making an eye doesn't help.];
        B[ls];W[ps];B[lq]
        C[Although White has "one eye against no eyes", but Black has enough outside liberties to easily win the semeai.]
        )
    )
)
    (;
    B[sr]
    C[Looks good enough, but ...];
    W[or]
    C[... White can dodge to here.];
    B[ps];W[rs]
    C[White has time to ruin the corner eyes, and Black cannot catch the 6 stones.];
    B[lq]
    C[For example ...];
    W[ls];B[ms];W[ns];B[qs];W[ks]
    )
    (;
    B[lq]
    C[Too slow.];
    W[ls];B[ns]
    C[Now this tesuji fails.];
    W[ms];B[os];W[or]
    )
    (;
    B[ls]
    C[Bad timing.];
    W[os];B[ms];W[lq]
    C[Now Black has a liberty shortage.]
    )
    (;
    B[os]
    C[Also looks promising, but ...];
    W[or];B[lq];W[ls];B[ps];W[ns];B[ps];W[ks]
    C[.. Black has nothing.]
    )
)

