This brain-teaser was shown to me by Ed Lucas of Tempe, AZ:

NORTH
-- 10 6 5 J 9 8 A Q J 10 8 6 5
	YOU (East)
6 by South	8 2 K 8 7 4 Q 10 3 9 7 4 3

North opens 3 and South bids 6

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Partner leads the 2 (Standard leads). 

You play the K and declarer plays the Q!

What is going on, and what do you do next?

Scroll down for answer.

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I know -- this looks too easy for an experienced player.

Partner surely has underled his hearts, with the suit-preference deuce (from A J 9 3 2) to get his club ruff. Did you give it to him?   Nice.  That's what declarer wanted.  He has made a brilliant falsecard, for the entire deal is:

	-- 10 6 5 J 9 8 A Q J 10 8 6 5
6 4 3 J 9 3 2 K 6 4 2 K 2		8 2 K 8 7 4 Q 10 3 9 7 4 3
	A K Q J 10 9 7 5 A Q A 7 5 --

Anything but a club at trick two defeats the contract. Did you fall into the trap? Give declarer full credit.