Opening 1N With A 5-Card MajorIn the highly regarded book, Points Schmoints!, Marty Bergen says to always open 1N with a balanced hand (at least 5-3-3-2), even if you have a 5-card major. He says: "There are absolutely no exceptions." (emphasis is his).
In the equally regarded book, Standard Bridge Bidding For the 21st Centry, Max Hardy says that before opening 1N with a 5-card major, three conditions must be met involving
BidBase presently favors Bergen's approach, but Hardy's book is highly recommended and after reading it, you may wish to change the database to agree with his approach.
It should be noted that liberally opening 1N with a 5-card major makes Puppet Stayman (for uncovering the 5-card major) more important.
Opening 1N With A 6-Card MinorHardy also provides guidelines for opening 1N with a 6-card minor. We have always thought two doubletons did not a balanced hand make, but Hardy calls 6-3-2-2 and 5-4-2-2 hands "semi-balanced" and provides guidelines for opening them 1N. We have followed these guidelines in BidBase for Strong NT only.
BidBase believes that if playing a weak NT (10-12, 11-13, 12-14), you are better off bidding a 5- or 6-card suit, so we have such entries for opening 1N hard coded for 15-17 HCPs.
How Many Points For Game in NT?
Following is a summary of this subject from BridgeBears.com:
Most players play that 25-26 HCPs are needed for game in notrump. A 24-point game is 50-50, but hands should be adjusted down a point for honors in a suit with no smaller cards (e.g.: KJ and nothing else) and -1 for 4-3-3-3 distribution.
The article linked above also says to deduct a point for holding 4 cards in a minor suit that partner has bid. According to the author, simulation calculates that with the fits shown that 3N makes the percentage of the time shown:
Note that the 1N opener could have 18 or even 19 HCPs but has 1 or 2 deductions getting his hand value down to 17, allowing him to open 1N. There are also some adjustments which make a hand play stronger, such as a lot of intermediates.
But as responder, we do not have to worry about opener's adjustments. We just assume that after adjustments, his hand value is in the 15-17 point range.
So if you have 9 points after adjustments, you should bid game because your minimum partnership total is 24 points.
If you have 8 points, you can bid 2N and partner should bid 3N with 16-17 points and pass with 15.
The problem is what to do with 7 adjusted points? If you bid 2N, opener bids 3N with 17 adjusted points and passes with 15, but what does he do with 16? Obviously 15 + 7 doesn't get you to even the 24 needed as a minimum for game.
This question is not addressed in the article, but it would seem right to bid 2N if you are certain that partner would have adjusted his points, and/or if playing against weaker opponents or if playing IMPs rather than Matchpoints where 3N down 1 would probably be close to 0 while 1N (assuming you pass) making 3 would not be a disaster since few, if any, pairs will be in 3N with 16 HCPs opposite 7.
For more on hand valuation, see the CardShark BidBase HandVal program and its documentation file.