Source: “Case for the Defense”
Victor Mollo
Victor Mollo
Wikipedia:Victor Mollo (St Petersburg 17 September 1909 – London 24 September 1987) was a British contract bridge player, journalist and author. He is most famous for his “Menagerie” series of bridge books, depicting vivid caricatures of players with animal names and mannerisms through a series of exciting and entertaining deals—bridge fables of a sort. Mollo attended Cordwalles School but neglected his studies and devoted himself to bridge. As an editor in the European service of the British Broadcasting Corporation, he began to write books and articles on the game. After retirement in 1969, Mollo started to write even more extensively, and up to his death in 1987 he wrote 30 books and hundreds of articles. He was also active in developing bridge cruises, mostly in the Mediterranean. Dealer South. Neither VUL
West North East South
  Pass
Pass 1 Pass 1
Pass 2 Pass 2
Pass 3 Pass 3NT
Pass Pass Pass
Contract: 3NT West leads 3
7 6 A Q J 10 9 A K Q 7 6 3
A J 4 Q J 10 7 K 8 3 2 10 8

Which card should East play?

Answer:

A.

There isn’t a moment to lose. Seven ready-made tricks are on the table. If declarer has the K it will be his eighth and the A will be the ninth.

Couldn’t West, not South, have the A? Possibly, but then West has an entry and there is no purpose in holding up the A.
7 6 A Q J 10 9 A K Q 7 6 3
K 10 8 3 2 6 5 3 2 5 J 9 5 A J 4 Q J 10 7 K 8 3 2 10 8
Q 9 5 A K 9 8 4 7 6 4 4 2