NEGATIVE INFERENCE

This refers to information gathered of deduced from the failure of a player to take a specific and/or expected action during the bidding of the hand and/or the play of the hand, or both. An illustration of the importance of this feature being calculated in the strategy of the declarer is shown below:

	A1082 84 AQ104 J64
KQJ64 AJ2 K763 K		973 K10653 985 92
	5 Q97 J2 AQ108753

South	West	North	East
Pass	1	Pass	Pass
2	2	3	3
4	Pass	5	Pass
Pass	Pass

West leads the King of Spades to the first trick. By Negative Inference, the declarer has reason to believe that if West had held both the Ace and King of Hearts, that West would have lead the Ace of Hearts. Since the lead was the King of Spades, this marks East as holding the Ace or King of Hearts. East can not hold the King of Clubs and the Ace and/or King of Hearts, otherwise East would have responded at his first chance to bid. However, East passed on the first round.

This logic or Negative Inference also leads South to assume that West is marked with a singleton King of Clubs, and therefore South does not finesse for the King of Clubs, but rather, on the second trick, leads trump from the dummy and plays his Ace of Clubs, falling the singleton King, held by West.

Using the assumption that West has to hold the King of Diamonds for his opening and rebid in Diamonds, South finesses successfully West for the King of Diamonds and takes a total of 11 tricks to fulfill the contract. The bidding substantiated the correct assumption of the declarer, which allowed the declarer to successfully and negatively infer the location of the key cards.

It is true, to some extent, that many players disregard the importance of the Negative Inference principle. There are many other clues during the bidding and play of the hand, which provide important information needed to make the contract, but the principle of Negative Inference should not be underestimated.

 

 

If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.

 

 

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