The abnormal is hard to execute

Cory Doctorow, a Canadian-British blogger, journalist and science fiction author, wrote, "Abnormal is so common, it's practically normal."

At the bridge table, the abnormal happens rarely, and most of the time it is missed, especially on defense. It is hard to make a play that would normally be suicidal but is the only winner on a given deal.

How should West analyze this layout? South is in four spades. West leads the club queen. South wins with his ace and plays a low trump. From where should West hope to find four tricks?