This is one of the most beautiful proactive counting deals I have ever seen.
It was noticed and recorded by Suhas Vaidya at a Hirabaug monthly pairs event a couple of years ago.
West led the ♦ 2 and got his diamond ruff.
He switched to the ♥ J. South finessed the Q and led a spade to the A. South then played a club to the K, which held. (The ♣A was known to be with West, as otherwise East would enter at trick 3 to give one more diamond ruff)
Now, South pulled another spade and was at the crossroads.. did West start with 2 Spades or 3?? Would you finesse the ♠ J or play for the drop?
It is very difficult on the table, but this guess can be avoided. After the ♣K holds, South plays another club. West wins and plays a second heart. North wins the ♥ A and continues Clubs! West is known to have exactly 6 hearts and 1 diamond, and has shown 2 Spades. Did he start with 2-6-1-4 or 3-6-1-3?
-If both opponents follow to the 3rd club, West is known to have 3 Spades.
-If East shows out on the 3rd club, West had only 2 Spades, and the Q can be finessed.
-If West ruffs the 3rd club, then he started with 4 Spades, and the contract never makes!