The Free Lance-Star – 25 Feb 1946
Counting the known cards in a suit held by various players, next adding their amounts together and then subtracting that total from 13—that simple process constitutes about half of the entire procedure known as “card reading.” By doing that you sometimes can tell positively that a certain player holds a singleton ace, king or queen. You can then cash in on that information by dropping a lower honor with a higher one or by using a small card to forte out an ace, thereby saving your own secondary high cards.
Dealer: East. Neither side vulnerable
Identical bidding came on this deal at two tables of a duplicate tournament, and in each case West led the 
2. Both declarers played the Q from dummmy to tempt a cover by the K. At one table East fell for that, and the A killed his honor. Next that declarer led the 
Q to the K and the 
2 came back, bringing the J, K and A The 6 was led to the Q and the J brought a discard of South’s last diamond.
The 5 was ruffed by East’s 7 and over-ruffed by the 8. South then reckoned thus: “West surely had four hearts for his double, I have six, so that leaves no more than three for East, to have bid as he did, he must have had the A, which would now be singleton, since he has played hearts to two tricks.”
So he led his 2 not his J, and forced out the A. East scored the 
A, and led the 5 for West to ruff. The 8 return was ruffed by the 4. The conserved 7 now dropped the 10, and the last two tricks were taken by the 9 and K.
At the other table, S. Garton Churchill a fine defensive player in the East read the 2 lead as showing exactly four cards, with South having just one. This he was sure would be the A because West would have led the A if he had it. So when the Q was played from dummy, Churchill played low. That enabled him to prevent a diamond discard later on the J and beat the contract_.