Posted 2008-August-27, 12:53
I agree with Brian that the holding that concerns me is declarer's AKxxx in clubs, which is why I also win the club and return one.
I am sure that there are holdings on which this may cost, but none sprang quickly to mind, while there are a number of easily-pictured heart layouts on which we don't want partner winning the club and concluding that we allowed him to do so expressly to permit a heart switch from, for example, J108x or Q9x.
As for which club to lead, the Queen appears to be clear for the very reason stated by Brian: AK9x.
I am adding my thoughts to Brian's primarily to add the point that partner's choice of a low diamond at trick 3 is of relatively little significance. At that juncture, he had 2 cards he could play (and he knew that we held 4 diamonds, since we would have continued the Q from KQx) but in a vacuum might have had 4 messages to send: I have something in hearts, i have something in clubs, I have something in both or I have nothing in either. The latter two would normally result in the same message... a neutral choice. But, on any view, there are 3 possible messages and only 2 cards to play. I think that the standard suit preference obligation here would be to use the higher diamond as a positive statement about hearts, and the lower as conveying no specific information about clubs... either we are neutral or we prefer clubs to hearts.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari