(;
AB[mo][np][op][pp][qp][rp][lq][mq][rq][sr]
AW[lo][kp][kq][kr][nq][oq][pq][qq][qr][rr][rs]
C[Black plays.

Source:
"Tesuji Problems"
Go World #26, p. 21, Winter 1981]
(;
B[mr]
C[Maybe the 1st thought is to descend.  But ...];
W[ps]
C[... White calmly plays the shape move here.  Black has no chance to prevent the 2nd eye.]
)
    (;
    B[ps]
    C[The next thought may be to take the vital point away from White.  But ...];
    W[mr];B[lr];W[ls];B[nr];W[ms];B[ns];W[ks]
    C[... eventually Black has to come back to connect at A.  Then White has time to capture the inside stones.]
    LB[mp:A]
    )
    (;
    B[nr]
    C[Correct.];
    W[or];B[ps]
    C[Now the timing for this placement works.];
    W[mr];B[lr];W[ns];B[ls];W[ks]
    (;
    B[mp]
    LB[ms:A][os:B]
    C[Incredibly, A and B become miai.  Not being able to form a 2nd eye, White dies!]
    )
        (;
        B[ms]
        C[Big mistake.];
        W[mp]
        C[With a liberty shortage, Black has to fight a ko.]
        )
    )
)

