Source: CAC 1975 Bulletin April 1975 My advice is to study the early discards and consider this point: From what holding would the defender most readily have made those discards? The answer often will resolve a critical guess. For example, a defender who holds A-5-3-2 or K-5-3-2 will discard from that suit more readily than if he had held Q-5-3-2 or J-5-3-2. That will give you a clue in situations of this kind: (1)
J 7 6
Q 9 4 A 5 3 2
K 10 8
  J 8 6 2  
A 5 3   Q 9 4
  K 10 7  
This is a side suit in a trump contract and declarer needs to establish one fast trick. In (1) East has made two early discards. Conclusion: he is more likely to hold A-x-x-x than Q-x-x-x. In (2) West makes an early discard. Conclusion: he is more likely to have discarded from A-x-x than from Q-x-x. (3)
A 8
J 9 4 K 7 5 3 2
Q 10 6
  K 10 8  
A 5 3 2   J 7 6
  Q 9 4  
In (3) East makes two early discards. When you play ace and 8 he follows with 5 and 7. Play him for K-x-x-x-x rather than J-x-x-x-x. In (4) West discards twice. He is more likely to have come down to A-x than to J-x; but if a low card to the king is headed by the ace, be inclined to play East for A-J-x. Such inferences are especially strong when dummy has what may seem to a defender to be an esta-blishable suit, as here: Dlr: South Vul: None Dealer North. None Vul
10 5 2 K J 6 3 A 7 3 8 6 4
9 3 Q 10 8 10 9 5 4 K J 7 3 J 7 A 9 5 2 J 8 6 A 10 9 5
A K Q 8 6 4 7 4 K Q 2 Q 2
West North East South
1 Pass 1NT
Pass 3 Pass 4
Pass Pass Pass
West leads 3 and South ruffs the third round. There is something to be said for leading a heart at once, putting West under some pressure if he holds the ace, but instead the declarer plays four rounds of trumps, discarding a diamond from dummy. (It is good play to keep the heart holding intact.) West throws a club and a diamond, East a club and a heart. After cashing three diamonds, South leads a heart and West plays the 8. South should finesse the jack. Why? Because of East’s heart discard. With A-9-x-x East, expecting the contract to depend on the heart guess, would not think it necessary to keep all four. But with Q-9-x-x he would not let a heart go, in case declarer held A-x. As so often is the case, the discard tells the story.