[twcho]

I held ♠876 ♥T2 ♦AJT75 ♣A96 hearing my LHO open 1♥, 1♠ from my RHO, 1NT from my left, 3♥ from my right and 4♥ from my left ended the auction. My pd led ♦K and dummy tabled his hand: ♠AKT94 ♥643 ♦432 ♣K7.

We play udca and obviously I was not going to overtake the K, so I played the 5 to encourage ♦ continuation, declarer followed with 6. My pd continued with ♦Q.

Which card should I play now to ask for a ♣ shift? Is ♦J the card that I should play to discourage pd from continuing ♦ if he still had any?

[jchiu]

Seems like a good time for the beer card to make a noble sacrifice. If he is out, this should be a clear suit-preference signal, otherwise he will start wondering where the ♦ AJ10 are and figure it out for himself.

[MFA]

This is not 'suddently' a lavinthal situation. You have encouraged trick 1 and your second card now shows count. ♦J, high = odd. Lavinthal is only on here, if everybody knows the distribution of the suit.

Observe how easy it is for partner now. With ♦KQx he knows that we don't have any more diamond tricks coming, and he will ask himself, why I didn't overtake the ♦Q, when he might have had a doubleton. And the answer is...