Source: WelshBridge Noviembre 2012…
“Purely Elementary my dear Watson” I was recently in Canada on holiday and came across an interesting article written by Steve Becker, in the morning paper:
Lead: 
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“Holmes” said Dr Watson as he showed the famous detective the accompanying hand, “here is a further example of the ill fortune that has recently plagued me. I contracted for six spades, and West led a club. I ruffed, drew trumps, played AKQ of hearts, discarding a diamond from dummy, then led a diamond to the ace and a diamond back.” “Alas, East showed out, and West took 2 diamond tricks to put me one down. I had expected East to have the king of diamonds, in view of his vulnerable three club bid, but to my dismay, defeat suddenly became my potion”
“My dear Watson,” Holmes replied as he refilled his pipe, “things are not always what they seem. Just as many enthusiasts who love the game dearly, but who fail to make full use of their deductive powers, you neglected to utilize clues you could have exploited”
“It was eminently correct to ruff the club, draw trumps and cash three hearts, but you should then have ruffed the six of hearts in dummy, and the jack of clubs in your hand. In so doing you would have learned that East had started with precisely two spades and four hearts. East’s vulnerable three-club overcall would have suggested that he had at least six, hence he could not have been dealt more than one diamond”
“Accordingly, you would next have played a low diamond from your hand and a low diamond from dummy! You could then sit back and reap the rewards of your astute analysis. Whoever took the trick would be forced to yield the slam”
“A marvellous diagnosis, by Jove” said Watson admiringly. “Purely elementary my dear Watson” the great detective replied.