♦K then ♥ Playing Declarer for original holding of : ♠ KQxx ♥ AQ4 ♦ J10xx ♣ A10 If you don't win partner can't attack ♥ before the ♦ suit is established for 9 tricks Note if Declarer has only 3♦ J10x W. can duck the ♦ - twice if necessary with ♦ Axx to allow his partner to win the ♦ K and return a ♥ However this play does not work if Declarer's hand is : ♠ KQxx ♥ AQ4 ♦ J10x ♣ AJ10 as when the ♦ J holds Declarer can cross to the Dummy with the ♠ A And lead the ♣ Q to make 9 tricks 3♠, 2♥, 1♦, & 3♣