A deal from a Manchester Bridge Club Duplicate on 21st June.
Dealer W NS Vul.
A quick auction leads to three notrump. West leads the spade four to East's king, while you throw a diamond from dummy. East returns a low spade and your queen wins. You run the club jack, but it loses to East's queen, who then returns another club with everyone following. The defence seems sub-optimal but can you take advantage?
You now have one spade, three heart, two diamond and four club tricks for a total of ten, while the opponents have taken two. So the conditions are right for a squeeze for the eleventh trick. Only one opponent can have long hearts and diamonds; also East presumably has the spade ace so your jack of spades is a squeeze threat. If West has the length in both red suits, then she can be squeezed. Cash the other top club, return to hand with the heart ace and cash the rest of the clubs coming down to this end position.
If West started with at least four hearts and three diamonds, as was the case, then she is forced to unguard one of the red suits and you can make the rest of the tricks. If East had started with the spade ace and three diamonds, then crossing to the diamond king and cashing the top hearts will squeeze her in spades and diamonds. However, if East has the heart guard and the spade ace you haven't got the entries to squeeze her in the majors.