You won't find this East hand among the examples in most textbook discussions of three-level openings, but no doubt influenced by the vulnerability and facing a passed hand, East elected to open 3.

 South had a marginal hand for direct action opposite a passed partner but this time all was well and North had plenty in reserve to raise.

North-South vulnerable West deals

A 9 2 Q J 10 6 3 Q 6 Q 4 2

K 7 6 8 7 4 2 10 9 7 5 4 A

5 4 9 5 A 8 3 K J 9 8 7 3

Q J 10 8 3 A K K J 2 10 6 5

West	North	East	South
Pass	Pass	3	3
Pass	4T	Pass	Pass
Pass

Opening Lead: A

 On West's lead of the A, East might play the nine, a high card to encourage a club continuation. If West held a second club, that would normally be the best defence.

 If West started with just one club, however, East would prefer to send a more useful message. He would like to tell West which suit to play next; he would like to send a "suit preference" signal.

 The most frequent message a "weak" three-bidder will wish to send is "continue my suit," but modern preempts (especially in third position) might well include a side ace, king, or void. When a player is known to have at least six cards in a suit, it costs nothing to use some of them as suit preference signals. East would play the 3 (low) to suggest a switch to the lower side suit, diamonds. He would play the J (high) to suggest a heart switch. With no preference for a side suit, he would follow with the eight or nine, suggesting a continuation.

 Here East played the 3. West switched to a diamond. East won the ace and played K, club for West to ruff. One down. With no help from his partner, West would probably switch to a diamond anyway, but here it was a sure thing. If West defends differently, declarer would cash ace-king of hearts, draw trumps ending in dummy, finessing against the king, and discard clubs on hearts.