It was in the Summer of ’83 while doing research that I was lucky enough to come across lost fragments of a Conan Doyle novella : The Adventure of the Four Kings. Here’s an excerpt:
Holmes was a deuced fine card player. He excelled at partnership whist. Always he magically knew which card to play. When I marvelled at his flair for plucking out the right card, he would be incensed at my clumsy inability to see there was no magic: “Watson, don’t be a fool! Magic does not exist in my world, all is logic, plain simple ordinary logic, to which I merely apply my mind.”
“But,” I fawned, “when you held the A,Q of Clubs you declined to lead that suit, and thereby, later in the play of the hand you were able to capture the K of clubs held by the player on your right. How did you know it was there? Magical!” I sighed.
“Watson, you half brained idiot,” he commented, “I did not KNOW the King of Clubs was on my right. How could I? I am no sorcerer. But since I did not hold said card there was ever a possibility of its being on my right.”
“Yes, Holmes, but that’s only a 1 in 3 chance and 33% is no solution!!” I said, chuffed to have spotted a flaw in his statistical reasoning.
“Doh! Pass the syringe, Watson, and I will endeavour to explain. You’re right of course to point out that among four players if I do not hold a particular card it will, logically, be in one of the other three hands. This is true. So. Let us consider those three options in detail.
If the king of clubs is on my left there is nothing I can do, except keep hold of my A Q of clubs and hope that player leads a club round to my hand so that I make both A and Q when I shouldn’t.
If my partner, you dear Watson, holds the K of Clubs then we shall have three tricks in the suit between us whatever occurs.
However, if the player on my right holds the K, I must at no time, under whatever pressure, lead any of my clubs whatsoever or I will give away a trick. I must always lead something else, almost anything else, so that that player is induced to lead the club suit to me! Whereupon I will magically, as you say, make both the A and Q.”
Thereupon, the great man, sank to the sofa with his electrical violin and lost himself in the staccato rhythms of his dub-step remix Brahms quintet…
You should NEVER lead an Ace unless you also have the king. Never. You should NEVER lead a low card from a suit headed by the Ace. Never. Here’s why. It will cost you. The incredibly few times it might – just – be right to do so will far be outnumbered by the myriad times it’s wrong.
AQxxx ........ J10xx
Lead a low card away from the Ace and now declarer makes that King. OK, so lead the Ace?
AQxxx ........ J10xx
Lead the Ace on this layout and again you give away a trick; lead low and you also give away a trick.
In both these situations you want the lead to be toward your holding in the suit. You must wait. Bide your time. Find another lead. You and partner may have bid this suit, but when partner supported you they did not promise the king. They promised four cards. Any four cards. Do not give to declarers tricks they do not deserve.