(;
AB[kq][lq][mq][oq][or][pq][kr][nr][js]
AW[jp][kp][lp][mp][np][op][pp][qp][jq][jr][nq][qq][ir][pr][ps]
C[Black plays.

Source:
    From one of the old classic collections.]
(;
B[ms]
C[Careless.];
W[os]
C[White ruins the 2nd eye, and Black has no corner aji.];
B[ns]
C[For example ...];
W[ls];B[mr];W[ks]
C[Black collapses.]
)
    (;
    B[mr]
    C[Too slow.];
    W[ls]
    C[Black has only one eye, and no corner aji.]
    )
    (;
    B[ls]
    C[Also too slow.];
    W[mr]
    C[For example ...];
    B[ms];W[ns];B[lr];W[os]
    )
    (;
    B[qr]
    LB[os:A]
    C[This 1st move is the correct common tesuji that many players see immediately.  Black now has a forcing move at A.

But this position is not so simple.]
    (;
    W[rr]
    C[The strongest defense.]
    (;
    B[os]
    C[Forcing immediately falls into a trap.];
    W[mr];B[qs];W[lr]
    C[Black only has one eye.]
    )
        (;
        B[ms]
        C[Also fails.];
        W[os];B[rs]
        C[Too late!];
        W[qs];B[ns];W[qr]
        C[Black has only one eye.]
        )
        (;
        B[rs]
        C[The only move!];
        W[qs];B[os]
        C[Now this atari carries a follow-up threat.];
        W[mr];B[qr];W[lr]
        C[White captures 5 stones, but ...];
        B[rq]
        C[... Black lives in the corner.]
        )
    )
        (;
        W[mr];B[ms];W[os];B[lr]
        LB[ks:A][qs:B]
        C[A and B are miai for Black.]
        )
    )
)

