(;
AB[rn][ro][mo][no][oo][po][sp][mq][pq][qq][lr][or][os][qr][qs][ps]
AW[pp][qp][rp][nq][nr][ns][oq][rq]
C[Black plays.

Source:
    Korean mid-level tsumego pamphlet.]
(;
B[sq]
C[Too slow.];
W[rr];B[rs];W[sr];B[op];W[so]
C[With extra liberties, White wins the semeai.]
)
    (;
    B[sr]
    C[Better, but ...];
    W[rr];B[rs];W[sq]
    C[... Black only has a ko.];
    B[op]
    C[Ko.]
    )
    (;
    B[op]
    C[Cutting immediately doesn't work either.];
    W[rs];B[rr];W[sr]
    C[Only a ko again.]
    )
    (;
    B[rr]
    C[Looks good, but ...];
    W[sr]
    C[... White ruins the corner eye.]
    (;
    B[op];W[rs]
    C[Black still only has a ko.]
    )
        (;
        B[rs]
        C[Preventing the ko doesn't help.];
        W[op];B[so];W[sq]
        C[White has enough liberties to win the semeai.]
        )
    )
    (;
    B[rs]
    C[Only this strange looking move works!]
    (;
    W[sr]
    C[White takes the vital point, but ...];
    B[op]
    C[... White now has a liberty shortage.];
    W[rr];B[qo]
    C[Captures the 6 stones.]
    )
        (;
        W[op];B[sr]
        C[Black makes miai of connecting out or making 2 eyes.]
        )
    )
)

