-	'Impossible Distribution'

- W/none    dummy        5 4 3 K Q J 5 3 7 3 2  10 4 e 8 6      you 7 6 4 A K Q J 8 6 J 2

- WEST---- 1 Double* 3 Pass   - NORTH - Pass  Pass Pass Pass EAST---- 1NT 2 4 SOUTH 2 Pass Pass    * extra’s

Your partner leads the 4 against West's 4-contract. You take the first trick, and declarer follows suit with the five-spot. You continue with another high diamond because partner might have a singleton. Much to your surprise, however, partner contributes the 10 while declarer follows with the nine. Impossible, as you are using standard leads: high-low showing a doubleton and both West and North have no diamonds left. The question is, should you continue the suit, hoping for Jack-third of trumps in North and a side Ace, or is a club shift indicated?

But why was partner suggesting an odd number of diamonds when in fact he only had two of them? The answer is that he is not interested in a ruff, as one normally is holding a doubleton. He probably already has a trump trick and was just waiting for a club shift. At the table a third diamond was led, which obviously meant the end of the defence, as is apparent from the full deal:
- -

- W/none Q 10 7 10 9 2 10 4 K 7 6 5 3 A K J 9 2 A 8 9 5 A Q 9 8 5 4 3 K Q J 5 3 7 3 2  10 4 e 8 6 7 6 4 A K Q J 8 6 J 2

-

One of Professor IMP's students remarked that the 'upside-down lead' was virtually impossible to find.
“Not so, young man,’’ the professor refuted, “North knew from the bidding that West had a strong hand. Before the play started it was highly likely that he would have to score not only a trump trick, but the K as well. Thus, his partner would have to get in and return a club. Rather elementary, I would say.”