(;
AB[ln][mn][nn][on][pn][qn][rn][mo][oo][op][fp][jp][kp][lp][np][nq][gq][iq][ir][qq][pr]
AW[ml][ol][ql][rl][im][km][kn][io][ip][qo][pp][pq][rp][jq][jr][kq][mq][mr][oq][nr]
C[Black plays.]
(;
B[or]
C[Looks obvious, but is a mistake!];
W[qr]
C[Maybe surprisingly, now Black has a liberty shortage.];
B[rr];W[rq];B[qs];W[qp];B[qr]
C[Can Black avoid a ko?];
W[sr];B[ro];W[os];B[po];W[rs]
C[Black has to fight a ko to save the lower right.]
)
    (;
    B[qr]
    C[Correct.  Black prevents the liberty shortage from the previous variation.]
    (;
    W[or]
    C[Connecting doesn't help.];
    B[qp]
    C[Now White is the only one with a problem.]
    )
        (;
        W[qp]
        C[Trying to capture the 3 stones doesn't work either.];
        B[or];W[rr]
        C[For example ...];
        B[rq];W[sq];B[so];W[sp];B[sr]
        )
    )
    (;
    B[rr]
    C[Whether this hane works is left as an exercise for the reader.]
    )
)

