The Rule of 20 in Bridge: When to Open a Light Hand
The Rule of 20 is a simple way to decide whether to open the bidding with a borderline hand. Add your high card points to the number of cards in your two longest suits. If the total is 20 or more, open the bidding. If it's less, pass.
Most players learn to open with 12 or more high card points. But some 11-point and 10-point hands are much better than others, because long suits take tricks too. The Rule of 20 helps you spot those hands. This guide explains how to count it, when it applies and when it doesn't, the Rule of 15 for fourth seat, and a few example hands.
How to Count the Rule of 20
It takes three steps:
- Count your high card points. Ace = 4, King = 3, Queen = 2, Jack = 1.
- Count the cards in your two longest suits. With 5-5 shape that's 10. With 5-4 it's 9. With 4-3-3-3 it's only 7.
- Add them together. If the total is 20 or more, open at the one level.
| Your hand | Points | Two longest suits | Total | Open? |
|---|---|---|---|---|
| 10 points, 5-5 shape | 10 | 5 + 5 = 10 | 20 | Yes |
| 11 points, 5-4 shape | 11 | 5 + 4 = 9 | 20 | Yes |
| 11 points, 4-4 shape | 11 | 4 + 4 = 8 | 19 | No |
| 11 points, 4-3-3-3 shape | 11 | 4 + 3 = 7 | 18 | No |
As the table shows, the rule rewards shape. A balanced 11-count usually isn't worth opening, but a shapely 10-count often is.
Why the Rule of 20 Works
Long suits take tricks after the high cards are gone. A hand with two 5-card suits can make a lot of tricks if partner fits one of them, even without many points.
Opening also has real benefits:
- It tells partner about your hand early, before the opponents start bidding.
- It makes life harder for the opponents, who now have to bid at a higher level.
- It helps partner on the opening lead if the opponents end up playing the hand.
Make Sure the Points Are in the Right Places
The Rule of 20 is a guide, not a law. Good players adjust it:
- Honors in your long suits are worth more. A hand with A Q in a 5-card suit is better than one with Q J doubleton.
- Short honors are worth less. A singleton king or a Q J doubleton often doesn't take the tricks its points suggest.
- Have a rebid ready. Before you open a light hand, think about what you'll bid next if partner responds in a new suit.
- Quick tricks matter. Many teachers add one more test: open only with at least two quick tricks (an A K counts as 2, an A Q as 1.5, an ace as 1, a K Q as 1 and a king with a small card as 0.5).
The Rule of 22
Some teachers use a stricter version called the Rule of 22. You add your high card points, the length of your two longest suits and your quick tricks. If the total is 22 or more, open. It's the same idea with a built-in check for defensive strength.
When the Rule of 20 Applies
The Rule of 20 is for first and second seat, when you're the first or second player to bid.
- Third seat: after two passes, many players open lighter, sometimes with a good suit and only 10 points, to suggest a lead or get in the opponents' way. If your partner opens light in third seat and you have a good raise, the Drury convention helps you find out how strong the opening is.
- Fourth seat: after three passes, you can simply pass the hand out. That's where the Rule of 15 comes in.
It's also only for opening at the one level. A 1NT opening, a strong 2♣ or a preempt each have their own requirements.
The Rule of 15 for Fourth Seat
After three passes, you have a choice nobody else had: if you pass, the deal is over and nobody scores. So you only want to open if your side is likely to come out ahead.
The Rule of 15 helps you decide. Add your high card points to the number of spades you hold. If the total is 15 or more, open. If not, pass the hand out. It's also known as Pearson Points.
Spades matter because they're the highest-ranking suit. If both sides have about the same strength, the side with the spades can outbid the other at the same level.
Example Hands
Example 1: A light opening that's worth it
You're first to bid and hold:
♠ A Q 9 7 4 ♥ K J 8 6 3 ♦ 7 ♣ 5 2 (10 HCP)
10 points plus 5 spades plus 5 hearts makes 20. Your points are in your long suits, and you have two good suits to bid. Open 1♠, the higher-ranking of your two 5-card suits.
Example 2: An 11-count that should pass
You're first to bid and hold:
♠ Q J ♥ Q 7 4 ♦ Q J 6 3 ♣ K 8 5 2 (11 HCP)
11 points plus 4 diamonds plus 4 clubs makes only 19. On top of that, your ♠Q J doubleton and lonely queens are weak cards. Pass, and wait to see what partner does.
Example 3: Fourth seat, open
The first three players pass. You hold:
♠ K J 10 8 5 ♥ A 6 ♦ Q 9 4 ♣ 8 7 3 (10 HCP)
Use the Rule of 15: 10 points plus 5 spades makes 15. With a good spade suit, you'll win the bidding battle if the points are split evenly. Open 1♠.
Example 4: Fourth seat, pass it out
The first three players pass. You hold:
♠ 6 3 ♥ A Q 8 5 ♦ K J 7 4 ♣ Q 9 2 (12 HCP)
12 points plus only 2 spades makes 14. If you open, the opponents may well have spades and outbid you. Many players would still open a 12-count here, and that's a reasonable choice. The Rule of 15 suggests a pass, which ends the deal with no score.
How to Practice on Bridge Champ
The computer players on Bridge Champ use the Rule of 20 when they decide whether to open, so you'll see light openings from them too. To practice your own judgment:
- Open a Bidding Practice table and turn on "Opponents must pass". Each auction is scored against the double dummy result, so you can see whether opening a borderline hand paid off. See the Bidding Practice guide.
- Use the Hand Editor to deal yourself 10-11 point hands with 5-5 or 5-4 shape and bid them again and again. See the Hand Editor guide.
If you're new to bidding, our guide on how to play bridge covers the basics first.
Frequently Asked Questions
What is the Rule of 20 in bridge?
It's a guide for opening borderline hands. Add your high card points to the number of cards in your two longest suits. If the total is 20 or more, open the bidding at the one level in first or second seat.
Do you always need 12 points to open in bridge?
No. 12 or more high card points is the usual guide, but the Rule of 20 lets you open some 10- and 11-point hands with good shape. Some balanced 12-point hands are also close decisions.
Does the Rule of 20 apply in third or fourth seat?
No. In third seat, many players open a little lighter. In fourth seat, players use the Rule of 15 instead: points plus spades must reach 15.
What is the Rule of 15 in bridge?
It's the fourth-seat version of the Rule of 20. After three passes, add your high card points to the number of spades you hold. If the total is 15 or more, open. Otherwise, pass the hand out.
What is the difference between the Rule of 20 and the Rule of 22?
The Rule of 22 also adds your quick tricks. You count high card points, the length of your two longest suits and your quick tricks, and open with 22 or more. It's a stricter version that checks your defensive strength too.
Summary
The Rule of 20 helps you open the right light hands: add your points to the length of your two longest suits and open with 20 or more. Use it in first and second seat, keep your honors in your long suits, and have a rebid ready. In fourth seat, switch to the Rule of 15.
Ready to try it? Play bridge free online on Bridge Champ, in your browser or in the app. And when you're ready for the next step, see our list of bridge conventions.