The Rule of 11

The Rule of 11 is one of those bridge tricks that sounds complicated but saves you mental energy once you get it. When partner leads a small card and you know it’s fourth best, you can instantly figure out how many cards higher than the lead are sitting in the other three hands. That’s powerful information.

What Is the Rule of 11?

Take the card partner led. Subtract it from 11. The answer tells you how many cards higher than that lead are in your hand, dummy, and declarer’s hand combined.

That’s it. If partner leads the ♠7, you subtract 7 from 11 and get 4. So there are four spades higher than the 7 between you, dummy, and declarer.

Why does this work? Because when partner leads fourth best (their fourth-highest card in the suit), they have exactly three cards higher than the lead. Since there are 13 cards in each suit, the math lines up perfectly. You’re basically accounting for where all the high cards are.

Fourth-Best Leads: The Foundation

The Rule of 11 only works when partner is leading fourth best. That’s the standard agreement for most partnerships when leading from a long suit. If you hold ♥KJ863, you lead the 6 (your fourth-highest heart). With ♣Q10742, you lead the 4.

Fourth-best leads give partner information about your length. Low cards suggest you have length in the suit. High spot cards (like an 8 or 9) typically show shortness or a broken suit.

When does partner NOT lead fourth best? Lots of situations:

Leading an honor (ace, king, or queen from a sequence)
Leading top of nothing (from three small cards)
Leading an attitude card (high encourages, low discourages)
Leading MUD or other non-standard agreements
Leading trump

If partner leads the ♥K, you can’t use the Rule of 11. If they lead the ♠2 and you know they play third-and-fifth leads, forget about it. The rule is tied specifically to fourth-best leads.

Using the Rule of 11 as Declarer

Declarer sees dummy and their own hand. When the opening lead hits the table, you have more information than anyone else. The Rule of 11 tells you exactly where the high cards are.

Say you’re playing 3NT and the opening lead is the ♠6. Subtract 6 from 11: five cards higher than the 6 are divided between your hand, dummy, and third hand. If you can see all five of those cards between your hand and dummy, then third hand has nothing higher than the 6.

That changes everything. You know you can duck the first trick completely, letting RHO win with a spot card. When they return the suit, you can safely finesse or make the right play because you know the exact distribution.

Example 1: Declarer’s Dream

You’re in 3NT. LHO leads the ♦5.

Your hand: ♠ A83
♥ KJ4
♦ Q97
♣ AQ62

Dummy: ♠ K72
♥ A103
♦ A83
♣ K1054

The ♦5 lead: 11 minus 5 = 6 cards higher than the 5 in the other three hands.

Between your hand and dummy, you can count: ♦A, ♦Q, ♦9, ♦8, ♦7, ♦3. That’s six cards.

RHO has nothing higher than the 5. You play low from dummy, RHO plays the ♦6, you play the ♦3. Now when you lose the lead and they continue diamonds, you know LHO started with ♦KJ105 (or similar). You can play the queen confidently, knowing the finesse is working.

Using the Rule of 11 as Third Hand

When partner leads and you’re sitting third seat (declarer’s RHO), the Rule of 11 helps you decide which card to play. You can see dummy and your own hand. Do the math and figure out how many high cards declarer has.

If the answer is “zero” or “one,” you know exactly how to defend. Play the right card to force out declarer’s stopper or to preserve your own entries.

Example 2: Third Hand Defense

You’re defending 3NT. Partner leads the ♠4.

Dummy: ♠ Q72
♥ K86
♦ AJ4
♣ Q1053

Your hand: ♠ AJ95
♥ 754
♦ 1082
♣ K84

The ♠4: 11 minus 4 = 7 cards higher than the 4.

Dummy has the ♠Q72 (three cards). You have ♠AJ95 (four cards). That’s all seven.

Declarer has no spade higher than the 4. Play the ♠9. It wins the trick because declarer can’t beat it. Now you cash your spades and set the contract before declarer gets going.

If you mindlessly played the ♠J (third hand high), dummy’s queen would win and declarer would have a spade stopper they didn’t deserve.

When the Rule of 11 Doesn’t Apply

The Rule of 11 is not universal. It breaks down when:

Partner isn’t leading fourth best - If they’re leading top of a sequence, an honor, or using a different carding agreement, the math doesn’t work.
Trump leads - Partners rarely lead fourth best in the trump suit. They might lead a singleton, top of a doubleton, or some other tactical lead.
Short suit leads - A lead from three small cards (top of nothing) or a doubleton isn’t fourth best.
Attitude leads - Some partnerships lead high to encourage, low to discourage. That’s incompatible with fourth best.
Against suit contracts - Opening leads against suits are often singletons, doubletons, or top of sequences. The Rule of 11 works, but you need to confirm it’s actually fourth best.
Partner is a weak player - If partner doesn’t know what fourth best means, the rule won’t help. Sorry.

Example 3: When It Fails

You’re defending 4♥. Partner leads the ♠Q.

This is obviously not fourth best. It’s top of a sequence (QJ10) or a short suit honor. Don’t try to use the Rule of 11. Just defend normally based on what the queen lead shows in your partnership agreements.

The Rule of 12 (For Third-Best Leads)

Some partnerships lead third-and-fifth instead of fourth best. When leading from a five-card suit, they lead their third-highest card. The Rule of 11 doesn’t work here, but the Rule of 12 does.

If partner leads third best, subtract the lead from 12. That tells you how many higher cards are in the other three hands.

The Rule of 12 sees less use because third-and-fifth isn’t as common as fourth best. But if that’s your partnership style, adjust your mental math accordingly.

Common Mistakes with the Rule of 11

Mistake 1: Applying it to honor leads

The opening lead is the ♥K. Don’t subtract it from 11. King leads show specific holdings (AK, KQ) and aren’t fourth best.

Mistake 2: Forgetting to count dummy

You’re declarer. The lead is the ♣7. You do 11 minus 7 = 4, then look at your hand and see three clubs higher than the 7. You think, “Great, RHO only has one high club.”

Wrong. You forgot to count dummy. Check dummy’s clubs too. If dummy has the ♣Q, that’s your fourth card. RHO has zero, not one.

Mistake 3: Trusting it in suit contracts without context

Against notrump, opening leads are usually from long suits where fourth best applies. Against suit contracts, leads are wilder. A ♠7 might be fourth best from length, or it might be top of a doubleton. Use the Rule of 11 carefully and confirm it makes sense with the bidding.

Mistake 4: Miscounting

This is just arithmetic, but people mess it up. Lead is the 6. Count carefully: 11 minus 6 is 5, not 4 or 6. Then count the actual high cards in sight. Double-check before making a critical defensive play.

Example 4: Catching a Mistake

You’re defending 3NT. Partner leads the ♦8.

Dummy: ♠ 1064
♥ QJ7
♦ KJ5
♣ A1082

Your hand: ♠ KJ73
♥ 863
♦ A94
♣ J64

The ♦8: 11 minus 8 = 3 cards higher.

Dummy has ♦KJ5 (three cards). You have ♦A94 (two cards, since the 8 is the lead). That’s five cards, not three.

Something’s wrong. Partner didn’t lead fourth best. Maybe they led from ♦Q1082 (top of an interior sequence) or from shortness. Adjust your defense accordingly and don’t rely on the rule this time.

Why Bother Learning This?

The Rule of 11 is optional. Plenty of good players don’t use it consciously. But it speeds up your card reading and gives you certainty in close situations.

As declarer, it helps you place cards and make the right percentage plays. As defender, it tells you when to win, when to duck, and which card to play third hand. That’s worth a little mental arithmetic.

Once you’ve used it a few times, the calculation becomes automatic. Partner leads the ♠5, you instantly think “six cards higher,” count what you see, and know what declarer has. It’s one less thing to puzzle over.

Perfect for those moments when you’re staring at dummy wondering if you should finesse or play for the drop. Let the math decide.