"Impossible switch"

Defenders frequently face a difficult switch in the middle of the game. As in the diagram below, after South pass, West open the bidding with just 2♠ (week-2), North double for take out, East pass, and South jump to 4♥. After think quite a while, North pass with 19 HCP. West start with ♠A and continue spade after you make a discard. How would you defend this hand.

	♠ Q 10 4 3
	♥ A 9 4
	♦ A Q 4 3
	♣ A K
		East
		♠ void
		♥ Q 10 8 7 2
		♦ 6 5
		♣ 10 x x x x

Firstly, what will you discard? Most defenders will discard diamond on the first trick. Say, you ruff the second trick and see declarer play his ♠K. What will you return to beat the contract? If declarer has the ♦K and 5 cards hearts, nothing you can do. If declarer has ♠Kxx and 5 cards heart, declarer has 10 tricks. So, your hope is declarer has only 2 card spades and no ♦K. With this analysis, have you found the best return? The best return is diamond, and when you get another lead, lead your second diamond. This will break up the squeezed. So, don't ever discard your diamond. If you return other than diamond, West will be squeezed in diamond and spade. After a club return, won in dummy, declarer will cash the ♥A, shocked for a while and then give lead to you by ducking a heart. Win another club in dummy and finesse heart and another heart will squeeze west. Poor west is unable to guard both spade and diamond. The complete distribution as below:

	♠ Q 10 4 3
	♥ A 9 4
	♦ A Q 4 3
	♣ A K
West		East
♠A J x x x x x		♠ void
♥ void		♥ Q 10 8 7 2
♦ K 10 9		♦ 6 5
♣ x x x		♣ 10 x x x x
	Selatan
	♠ K x
	♥ K J x x x
	♦ J x x x
	♣ Q J

Can you see another way to defeat the contract? The easiest way is: don't ruff the second spade. Just discard and you will find declarer will have no way to land the contract. Defensive play is hardest part of the game in bridge.