The Rule of 20

For most of the twentieth century the decision to open came down to one count. You added up your high-card points and opened with 13, or with a good 12. Yet a 12-point hand with two five-card suits and a 12-point hand with a flat 4-3-3-3 shape are not the same hand, and the first takes far more tricks. The rule of 20, popularized by Marty Bergen, is the simplest widely used way to tell them apart.

Count your high-card points the usual way: four for an ace, three for a king, two for a queen, one for a jack. Then add the number of cards in your longest suit and the number in your second longest suit. If the total reaches 20, open the bidding at the one level.

The rule is a proxy for playing strength. Length is where tricks come from. A five-card suit opposite partner's three cards is a trump suit, and the fifth and sixth cards of a long suit win tricks that no honor card has to win for you. Two long suits also mean two short suits, and shortness means ruffing power once a fit is found.

A total of exactly 20 is where judgment starts. Most experienced players open these hands when the honors are in the long suits and pass when they are not. Compare two hands that both score 20.

• Honors in the long suits are worth more than their point count. The ♠AQJ in a five-card suit will take tricks, while the ♦Q sitting alone will often be wasted.
• Aces and kings are undervalued by the 4-3-2-1 scale and queens and jacks overvalued. A hand with two aces and a king is a sounder opening than a hand with three queens and three jacks.
• Quick tricks are the second filter many players add. Holding a 20 count, they open only if the hand also has two quick tricks (an ace or a king-queen in the same suit counts one, an ace-king two).

Opening an 11-point hand changes the rest of the auction, and partner is entitled to know you might do it. Three things follow.

1. 1.Your rebid must be minimum. A light opener never reverses, never jumps, and passes any invitational bid. Partner will play you for 12 or 13 points. Do not bid as if you held them.
2. 2.Partner's game tries need a little more. If your partnership opens all rule-of-20 hands, responder should invite with a good 11 rather than a bare 10, because opener's average hand is lighter.
3. 3.Opening light is about shape, not points. A balanced 11-count scores 18 or 19 on the rule of 20 and stays a pass, which is exactly what the rule intends.

In third seat, after two passes, many partnerships open even lighter than the rule of 20 suggests, because responder has already limited the hand by passing and a light opening makes the opponents' auction harder. Drury exists precisely so that partner can check whether a third-seat opening was real.

In fourth seat the question changes. If you pass, the deal is thrown in and nobody scores. The traditional tool here is the rule of 15 (Pearson points): add your high-card points to the number of spades you hold and open if the total is 15 or more. The spade count matters because whoever owns the spade suit wins the fight for a part score.

What is the rule of 20 in bridge?

The rule of 20 is a guideline for opening light, shapely hands. Add your high-card points to the number of cards in your two longest suits, and if the total is 20 or more, open at the one level.

Does the rule of 20 apply to notrump openings?

No. A 1NT opening promises a balanced hand in a stated range, usually 15 to 17 points, and the rule of 20 does not override that. It decides whether to open one of a suit with a shapely hand.

Should I count distribution points as well as the rule of 20?

Not at the same time. The rule of 20 already rewards length, so adding length points on top counts the same thing twice. Use one method or the other.

What is the difference between the rule of 20 and the rule of 22?

The rule of 22 adds your quick tricks to the rule-of-20 total and asks for 22. It keeps the shapely hands the rule of 20 opens and filters out the ones whose points are all queens and jacks.

Is the rule of 20 part of Standard American or Acol?

Neither system requires it. It is a hand-evaluation guideline that partnerships add to any system. The ACBL's Standard American Yellow Card describes openings as 13 points or a good 12, and many SAYC players use the rule of 20 to define what a good 12 is.