Rule of 11
The Rule of 11 in bridge is a technique you can use for calculating the location of unseen cards in the suit that has been led when the opening lead was the 4th highest.
How to use the rule of 11
- Subtract the value of the card led from 11 to give the total number of higher cards
- Count the number of higher cards you can see in dummy and your own hand
- Declarer will have the rest!
You are South on the following hand and partner leads the ♦7 against West's 3NT contract. Dummy plays low.
How can you use the rule of 11?
Subtract the value of the card led from 11.
Partner leads the 7 so you subtract from 11 which leaves 4.
Count the number of higher cards you can see.
You can see three cards higher than the 7 in your hand and one card higher than the 7 in dummy for a total of 4.
Calculate how many cards declarer has that are higher than the one led.
There are 4 cards higher than the 7 in your hand, dummy and in declarer's hand. Three are in your hand, 1 is in dummy. That means declarer has no cards higher than the 7. You can let partner's 7 hold the trick and keep your Ace to cover dummy's K.
Here is the full hand:
Partner's ♦7 wins the first trick!
Using the rule of 11 as declarer
West leads the ♦3 against South's 3NT contract. South calculates that East has one card higher than the 3 which must be either the K, Q, T or 8. If West held the KQT3 he probably would have led the K so West either has KT83, QT83 or KQ83. Two times out of three, West will have the ♦T so South plays the ♦7 or ♦9 from dummy, hoping for an honour from East.
4th highest leads and the rule of 11
The rule of 11 only works when the opening lead was 4th highest. Let's take a look at a hand to see what that means.
This time you're on lead against 3NT and you've chosen to lead a heart. Simply count down from the Ace. Ace = 1st, Q = 2nd, 7 = 3rd and the 5 = 4th highest. The 5 is the card to lead!
What if the 4th highest happened to be a high card? Well, it won't be! With AKJT, for example, the T is the fourth highest but that would be a very unusual lead. You'd lead the ace from this holding, top of a sequence.
Ok, then what.