(;
AB[ss][nr][nq][np][so][ro][oo][rn][qn][pn][on]
AW[ps][sr][pr][sq][pq][sp][pp]
C[Black plays.

Source:  unknown]
(;
B[rp]
C[The obvious first try, but ...];
W[rs]
C[... White has this simple response to live.];
B[rq];W[rr]
C[White already has 2 eyes.]
)
    (;
    B[rq]
    C[Another good looking try, but ...];
    W[rr]
    C[... White easily makes eye-space.];
    B[qq];W[qr]
    )
    (;
    B[qq]
    C[Another try.];
    W[rs]
    C[Again, White has this simple response to make eye-shape.];
    B[rq];W[rp];B[qp];W[qr]
    C[White lives.]
    )
    (;
    B[rs]
    C[The first try so far that requires White to think about the correct response.];
    W[rp];B[qp];W[qq];B[rr];W[qo];B[po];W[qs]
    C[Black only has a ko.]
    )
    (;
    B[rr]
    C[The only move that works!];
    W[rq];B[rs];W[qp]
    C[The only chance to make enough eye-space.];
    B[rp]
    C[Black seems to effortlessly kill White, but ...];
    W[qr]
    C[... White has this nasty surprise!];
    B[qq];W[rq]
    C[With this under-the-stones play, now Black has a liberty shortage.];
    B[sq];W[qs]
    C[White seems to have a ko for life, but ...];
    B[sr]
    C[... now Black is the one with a nasty surprise!];
    W[sp];B[sr]
    C[White has no good answer to this second under-the-stones tesuji.];
    W[sq];B[rr]
    C[White has only one eye.]
    )
)

