(;
AB[rr][rq][qq][qp][qo][po][oo][op][oq][mp][lo][lq][kq][jq][iq][ns]
AW[pr][qr][pq][pp][or][rs][nq][mq][lr][kr]
C[Black's response to White's marked play?

Analysis:
    Myron Souris]
TR[kr]
(;
B[jr]
C[White's marked play is increasing eye space at an alarming rate.  Surely Black must restrict White by descending here.];
W[ms]
C[But then White takes the vital point.];
B[ks];W[nr];B[js];W[os];B[ls];W[qs]
C[White can recapture to preserve the 2nd eye.  Black's attack has failed.]
)
    (;
    B[ms]
    C[Almost unbelievably, this famous tesuji kills White.]
    (;
    W[jr];B[ir]
    (;
    W[js]
    C[White's stiffest defense.];
    B[mr]
    C[After this cut, White must capture the 3 stones.];
    W[os];B[is];W[nr];B[ls];W[ks];B[ms]
    C[Black plays "under the stones" on the vital point for the 2nd time!];
    W[qs]
    C[A vain attempt to make 2 eyes.];
    B[mr]
    C[And White collapses.]
    )
        (;
        W[mr];B[js]
        C[This powerful hane is the killing response almost regardless of any previous White play.];
        W[qs];B[os];W[ks];B[nr]
        C[Black forms a dead shape.]
        )
        (;
        W[nr];B[js];W[ks];B[qs]
        )
        (;
        W[qs];B[js];W[mr];B[os]
        )
    )
        (;
        W[qs];B[jr]
        C[This descent is the killing response to almost regardless of any previous White play.];
        W[mr];B[ks];W[ls];B[os]
        C[Black forms a dead shape.]
        )
        (;
        W[nr];B[jr];W[qs];B[ks]
        )
        (;
        W[mr];B[jr]
        (;
        W[qs];B[ks]
        )
            (;
            W[ks];B[qs]
            )
        )
    )
)

