
Standard American 21
The Rubber Bridge Player's Guide For The 21st Century
By John Sheridan Thomas
Chapter 6: The Majors
Opening Bids
In the first or second seat, opening the bidding at the one-level promises 13 points while the upper limit is about 20 points. The Strong two club opener is employed for most hands above 20 points.
Two-suited hands are more challenging. With minimal opening values, favor the higher-ranked suit because it can be troublesome or impossible to show the second suit later. Strong hands (17 points or more) allow you more flexibility: you have the option of opening the lower-ranked suit then reversing into the higher-ranked suit at the second bid. This reversal describes your additional strength and distribution, and quite sensibly.

Five-Card Majors Verses No-trump
When you have 16 to 18 points and a five-card major, your hand qualifies for either a major suit or a 1NT opener. Standard practice is to open the major because it facilitates finding major suit fits. If partner does not have support you can revert to no-trump at the next round if no better choice presents itself.