Source: raysbridgeblog.wordpress.com por Ray Adams 
Poor Frank and Lucky Archie were at it again just the other night at the local bridge club. The winner would be determined by the result of the following exciting hand:
Dealer: North Vulnerable: NS
It was normal for South to become the declarer in a 3NT contract and also normal for West to lead the four of spades. It was also routine for East to win the ace and return a small spade. South would win the king, run the diamonds, and give up a club to the ace. Then all the Easts led a spade to partner’s queen and that would be that, as West would be out of spades. Making four for plus 630 to North/South. However a different scenario played out when Poor Frank sat East and Lucky Archie was in the declarer’s seat.West led the four of spades as usual. Poor Frank studied this card carefully and decided that his partner must be leading from three to the queen.
Therefore, declarer must hold king doubleton. Assuming his analysis was correct, Poor Frank foresaw that the defense’s key suit would be blocked if he made the normal play of the ace. He reasoned that if he let Lucky Archie win the first trick, then when Poor Frank got in with the ace of clubs, he could lead to partner’s queen and the subsequent return of a spade would mean the contract would fail. Readers can see that Poor Frank was absolutely correct. He inserted the nine of spades at trick one and Lucky Archie won the king.
Archie then ran the diamonds and a most unusual thing occurred. West assumed there was no future in spades and sluffed the five of spades and a heart. When a club was played, Poor Frank pounced with the ace and shot back a spade. West won the queen, but had no spade to return. Making five for plus 660 to Lucky Archie. This was a top for him and a bottom for Poor Frank and propelled Frank’s chief rival into first place that evening. As the players filed out, Poor Frank could be heard saying, “It was the perfect defense. We would have won and I would have beaten Archie.” Lucky Archie, on the other hand, said, “Frank is going to have to learn to cash his aces if he wants to beat me.” Most of the players agreed with him. “Poor Frank,” they said, “when will he learn?”