What makes a good convention? There are 4 factors:
Frequency – The more it comes up, the better.
Simplicity – The easier it is to remember, the better.
Effectiveness – The more you gain when it comes up, the better.
Cost – The less you have to give up in order to play it, the better.
Before your partnership adds a new convention to its system, you should analyze whether it will be beneficial or not under those four criteria.
I was thinking about it recently, and there is one convention that I play that hits a home run from that perspective, and surprisingly few people play it.
Say the auction starts:
1 p 1NT p
2 p 2NT p
?
You would like to be able to do all of the following:
Show 5-5 in the majors and force.
Show 5-5 in the majors and sign off.
Show 6-4 in the majors and force.
Show 6-4 i the majors and sign off **(more on this later).
Pattern out with 54(31) or 54(40) for choice of games purposes (or possibly for slam).
The problem here with natural methods is that you must choose whether 3and 3 cater to hand types 1 and 3, or hand types 2 and 4. Most people give up on hands 2 and 4, letting partner play 2NT in order to improve their game and slam bidding accuracy. However, there is a simple way to have your cake and eat it too.
Play 3 as a relay to 3. This will operate like lebensohl. Over 3 if you bid 3 or 3, it is to play. If you bid 3N it means you had a natural 3bid, so 5404 or 5413, enabling partner to pull with weak diamonds. This leaves a direct 3 and 3 as forcing. A 3 bid would be standard, showing a diamond fragment.
The cost of playing this is very small, you lose some room when you have a club fragment, but it is room that you usually won’t need anyways.
The simplicity of the convention could hardly be lower. You have to remember that 3 is a relay, that’s it.
The effectiveness of the convention is where it really shines. You no longer have to choose between leaving your partner in 2NT when you hold KQxxx AJxxx Q xx, or forcing to a ridiculous game. Same with a hand like KJxxxx AJxx Qx x.
I can already hear some of you saying, “But Justin, wanting to sign off with a 6-4 hand is impossible, because with a weak 6-4 I would have bid 2 not 2. Then when I bid 3 next, my partner knows I have a weak 6-4.”
It is very classical that weak 6-4’s bid spades, spades, hearts, and strong 6-4’s bid spades, hearts, spades. However, it is a very poor way to play. It is too important to introduce hearts over 1NT whenever you have 6-4, there are some hands where partner will pass you in 2but would invite or bid game over 2. And partner might just be 1-4 or 1-5 where 2is a much superior partscore (remember when partner is 2-3 he will correct to 2 unless his hand is very weak.) This does not even take into account suit quality issues, do you really want to bid 1then 2on Qxxxxx AKQx xx x?
But please, stop interrupting me. You know how I like to go off on tangents.
Back to the convention. The frequency of it is reasonably high, because it does not only apply to 1-1NT-2-2NT. It applies to these auctions as well:
1-1NT-2-2NT
1-1NT-2-2NT
1-1-2-2NT
Basically, it applies when opener has bid 2 suits, and neither of them was clubs. This is obviously because if you have bid clubs, bidding 3 is now a rebid of your second suit.
There will be some auctions where you have an extra step. If you think this might be confusing, I would recommend just leaving it idle, it is not worth it as it takes away from the simplicity of the convention and adds little to the effectiveness.
However, for completeness, the auction:
1 1NT
2 2NT
3 3
3
would have no meaning. I like to define it as 5404, whereas 3 then 3NT is 5413. Interestingly, you can do the same thing over 1-1-2-2NT-3-3, even though partner has bid spades naturally. A direct 3 would show a spade fragment, and having two ways to force in spades is not useful (and non forcing would not make sense… you are forcing too high if you don’t have a fit, and with a minimum 3541 you should be raising 1to 2to begin with).
Whatever your level, I recommend that you add this excellent convention to your arsenal, and start thinking about the right things before you add another objectively bad convention to your system just because it seems cool.