(;
AB[lm][mm][nm][qm][kn][ko][pn][qo][qp][qq][lp][lq][op][mq][pq][pr]
AW[lo][mo][oo][po][ip][kp][kq][mp][pp][oq][or][ir]
C[Black plays.]
(;
B[nr]
C[Attaching might look like a way to connect, but ...];
W[os]
C[... White can descend to win the semeai.]
)
    (;
    B[os]
    C[Black can squeeze here, but White has multiple possible defenses.]
    (;
    W[ns]
    C[Blocking is one possible defense.];
    B[np]
    C[But Black takes advantage of this hard to spot liberty shortage.];
    W[no];B[nq]
    C[Black wins the semeai.]
    )
        (;
        W[np]
        C[Simply capturing is also an obvious try.];
        B[nr]
        C[Black connects.];
        W[nq]
        C[Sente.];
        B[mr];W[nn]
        C[So White can live inside as compensation.]
        )
        (;
        W[nr]
        C[Also doesn't prevent the connection.];
        B[mr];W[ns];B[np]
        )
    )
)

