(;
AB[cr][bq][cq][dq][qq][dp][ep][fp][pp][bo][co][bn][fn][pn][qj]
AW[cs][br][dr][er][pr][eq][hq][nq][jp][lp][cn][dn][bm][dl][cj]
C[Black plays.

Source:
    Tesuji Dictionary, Vol. 1, Tsuke #90,
    Segoe Kensaku & Go Seigen, Ishi Press]
(;
B[iq]
C[A beautiful move.

If at a glance you can spot this best move and see all the ramifications, then you need to quit your day job and teach us go.]
(;
W[ip]
C[White must prevent Black from playing here to split the 2 white groups and to destroy White's bottom territory. ];
B[gq]
C[But Black has this clamp that exposes the inherent weakness in White's position.];
W[hr];B[gr]
C[But Black splits White anyway and takes the entire corner.]
)
    (;
    W[hp]
    C[White might also try to defend here.];
    B[gr];W[hr];B[gq]
    C[But Black still cuts off White with this order of plays.]
    )
)
    (;
    B[bs]
    C[A small gote endgame play.  White will ignore this atari to protect the weakness (around A) that the main line exposes.]
    LB[iq:a]
    )
)

