(;
AB[pd][pl][pm][on][oo][op][dp][mq][nq][pq][qq][rq]
AW[dc][ce][pn][po][pp][qp][rp][oq][or][nr][rr]
PL[W]
C[Does White need to respond in the lower right to the marked play?

Source:
Go World #25, pp. 46-47, January 1981
White:  Shiratori Sumiko 4P
Black:  Michael Redmond 1P
Commentary:  Rin Kaiho 9P]
TR[mq];
W[dk]
C[The game move.  Did White need to respond in the lower right corner?]
(;
B[jd]
C[Michael's game move.  See the variation.];
W[mr]
C[Interestingly, in the game White comes back here unnecessarily.

White's push prevents Black from descending here in sente, but ...];
B[lq]
C[... Black simply extends.  And later in the game, Black has the following sente sequence.]
PL[B];
B[qn];W[sq];B[ro];W[pr]
TR[lq][mr]
C[After this exchange, White would have preferred not to have made the marked exchange, i.e., if White had lived in the corner first, White would not make the marked exchange.]
)
    (;
    B[sp]
    C[Black's hane here doesn't work.];
    W[so];B[sq];W[rn];B[qr];W[rs]
    C[White has this tesuji to live.]
    )
)

