Here is a hand I saw played by Ralph Katz sitting South:
Note that Katz will go down immediately if West leads a diamond. However, West chose the reasonable lead of the ace of clubs.
Katz ruffed and visualized the East hand. This is what I infer that Katz was thinking: East had opened the bidding and, after rebidding his diamonds, should hold the ace and king of diamonds. West led the ace of clubs, so presumably has the king as well. Also, it appears that an unbalanced hand with length in clubs would justify West’s aggressive bidding. Therefore, it seems reasonable to assume that East holds the Q J of hearts to justify his opening bid.
Assume Katz visualized a hand like the one East held, do you see how he avoided losing one heart and two diamonds? He made his doubled contract! How did Katz Play?