(;
AB[ir][hr][kr][kq][jp][ip][hp][gq][mr][nq][mo][ko][kn][mn][np]
AW[kp][lp][lq][lr][ls][jo][io][ho][gr][fr][fq][fp][gp][gn]
C[Black plays.]
(;
B[mq]
C[Starting by reducing the outside liberties is too slow.];
W[js]
C[Some example sequences follow.]
(;
B[ks];W[jr];B[jq];W[hq];B[iq];W[hs];B[is];W[gs]
C[At best, Black only has a ko.]
)
    (;
    B[ms];W[jr];B[jq];W[hq]
    )
    (;
    B[jr];W[ks];B[is];W[iq];B[hq];W[gs]
    )
)
    (;
    B[jq]
    C[Making an internal eye here seems like a good idea, but ...];
    W[js]
    C[... White's eye-less group has too many liberties.];
    B[ks];W[hq]
    (;
    B[iq];W[gq]
    )
        (;
        B[mq];W[gq];B[ms];W[iq];B[jr];W[hs]
        )
    )
    (;
    B[ks]
    C[Making an internal eye this way also fails.];
    W[hq]
    C[For example ...];
    B[iq];W[jr];B[js];W[hs];B[mq];W[gs];B[ms];W[is]
    )
    (;
    B[js]
    C[The only way to make an internal eye that works.];
    W[hs]
    C[White must stop the 2nd eye.];
    B[jq]
    LB[iq:A][is:B]
    C[Amazing.  For 2 moves, Black has ignored reducing the White group's 5 liberties.

But now White must make 2 approach moves in order to eliminate the last liberties at A and B.];
    W[hq];B[mq];W[gs];B[ms];W[is];B[mp]
    C[Black wins the semeai.]
    )
)

