(;
AB[qr][pr][or][op][np][mp][lp][kq][jq][lr]
AW[rr][rq][qq][pq][pp][oo][no][mo][lo][kp][jp][ip][iq][ir][jr][kr]
C[Black plays.

Source:
    Unknown]
(;
B[mr]
C[The only move that works!];
W[lq]
(;
B[ns]
C[Best.];
W[ls]
C[And now Black has several moves to make 2 eyes.]
)
    (;
    B[oq]
    C[The only other move that lives, but ...];
    W[ns];B[qs];W[os];B[mq];W[nr]
    C[... White can choose to force this gote seki.  Black has no territory, so Black must make sure to have a big enough play elsewhere.]
    )
    (;
    B[nq]
    C[For example, this move fails.];
    W[ns];B[qs];W[ls]
    C[Black has only 1 eye.]
    )
)
    (;
    B[ns]
    C[An encouraging looking move that seems to make excellent eye shape, but ...];
    W[oq];B[nq];W[mr]
    C[... White's placement attack exposes Black's liberty shortage.];
    B[lq];W[qs];B[ps];W[nr]
    )
    (;
    B[lq]
    C[Connecting here seems reasonable, but ...];
    W[oq]
    C[... White can simply push in to reduce Black's eye space]
    (;
    B[nr];W[ls]
    C[Black can make only 1 eye along the bottom edge.]
    )
        (;
        B[nq]
        C[Blocking here is no better.];
        W[mr];B[ms];W[nr]
        C[Black dies from a liberty shortage.];
        B[qs]
        C[For example ...];
        W[os]
        )
    )
    (;
    B[oq]
    C[Connecting here also seems reasonable, but ...];
    W[ls]
    C[... this hane exposes the weakness in Black's shape.]
    (;
    B[mr]
    C[Too late.];
    W[qs]
    )
        (;
        B[ms];W[lq]
        C[Black's eye space collapses.]
        )
    )
    (;
    B[nr]
    C[Fails];
    W[oq]
    C[Simply pushing in is enough to keep Black to only 1 eye.];
    B[nq];W[lq]
    )
    (;
    B[ls]
    C[Fails];
    W[oq];B[nq];W[lq]
    )
    (;
    B[qs]
    C[Fails];
    W[mr]
    C[White takes the vital point.];
    B[ls];W[lq]
    )
)

