NORTH
 T85
 AKJ763
 K
 874
 AQ2
 852
 JT94
 AJ5
  643
 QT9
 A873
 T93
  KJ97
 4
 Q652
 KQ62
Dealer: North    Vul: NS   MP Scoring

West

Pass
Pass

North
1
2
Pass

East
Pass
Pass
Pass

South
1
3N

 3NT Lead Standard 

West chose to lead the J.
East won dummy's K and returned the 3, original 3rd best.
South followed with the 2 while a Granovetter ''obvious shift' from a 3 hand blinded point of view might have been in order.
What kind of standard does YOUR partnership have for that J lead?
Does it promise some minimum number of diamonds?
Does it promise additionally the T and at least 1 additional guards? (i.e. JTx)
Two additionals? (i.e. JTxx)
Would it promise, if less than 5 cards in this auction additionally at least the 8? (i.e. JT8x)
Additionally at least the 7? (i.e. JT7)

Do you have such standards for longer diamond suits in this auction?

West, missing the 8, at least know that East had almost certainly started with 4 diamonds.
The big question was: Underlead diamonds or break a new suit?
Could East really have the Q in this auction and return the 3?
Definitely possible, but already improbable.
At least it is an addition to a diamond continuation.
If South held the Q, then East had 3 diamonds to return while a South with the Q would have only 2 other diamonds that might include the 8.

West won the 2nd diamond and returned another won by declaring South's Q.
The J lost to East's Q.
East led back a diamond to West's 9.
NORTH
 T85
 AK763
 
 
 AQ2
 85
 
 AJ5
 

As West on lead, expecting East to have no points remaining, able to cash two setting aces, a bizarre idea occurred.
Lead a heart to a possibly dead 5 dummy tricks.
A forced spade return would net 2 spades and 1 club.
Why not? Is there really an alternative?

Down 3 was the result.
As declarer, do you keep a club in dummy instead of a 'winning' heart?