The Rule of 20 is used if your hand is "shapely" - ie very unbalanced.
How and When to Use The Rule of 20If you have a relatively good hand that has fewer than 12 points you might feel it is suitable for opening the bidding. How do you decide? This is when you use the Rule of 20. Take the total of your high card points and add that to the length of your longest two suits. If the total comes to 20+ then your hand satisfies the Rule of 20. You can open the bidding if you want to (note - you can pass if you would prefer to).
Take a look at some Sample Hands
(spades) A J 9 3
(hearts) 9 6 2
(diamonds) A Q 10 9 7
This hand has 11 HCPs and the two longest suits have 5 and 4 cards. If you add these together you get a total of 20, so this hand would be suitable for opening the bidding.
(s) 10 6
(h) K Q 8 3 2
(d) A J 9 5 4
This hand has only 10 points and the two longest suits both have 5 cards. Adding these together again gives us a total of 20, so this hand would also be suitable for opening the bidding if you wanted to.
(s) Q J 8
(h) 6 5
(d) A 8 2
(c) K J 9 6 3
This hand has 11 points. If you add that to the length of the longest two suits (5 and 3) the total comes to just 19. This hand doesn't satisfy the Rule of 20 and so isn't suitable for opening.
Notice that hand 3 is a balanced hand. The Rule of 20 works for unbalanced hands.
The rule of 20 is one of the many lessons, tutorials and activities that you can practice if you join No Fear Bridge for your 2 weeks' trial membership. Click Here to join right now.