[blml] Revoke established?

[Ed Reppert]

On Jul 10, 2006, at 11:05 AM, Alain Gottcheiner wrote:

>> The "circumstances" that make it a played card are declarer's  
>> indicating in some manner that it is a played card.  When the lead  
>> is made, dummy has a singleton, and declarer says, "Play it," it  
>> is played, notwithstanding that its rank and suit have not been  
>> named.
>
> A gesture with open hand, or a nod, will do.

Declarer says "play". What card is played?