[jallerton]

 hirowla, on 2014-June-15, 21:25, said:

Hi, I was wondering what modifications do you need to basic 2/1 to include a weak NT rather than a strong NT? I live in a world of weak NT bidders and have actually grown to like it!

One obvious one I can think about is after an auction of 1♥/1♠ - 1NT, what does a 2NT rebid mean (15-17 or 18-19)? I don't have an answer to that.

Any hints would be appreciated.

Thanks,

Ian

You ask about modifications, but compared to what? "Basic 2/1" is ill-defined and means different things to different people.

For example, I often play a rebid structure which allows me to handle all 5M332 hands after opening 1M. Using this style, the continuations after 1M openings will not vary depending on my NT (particularly useful if playing variable NT openings!).

Some strong NT players use a style whereby all 5M332 hands are opened 1NT if in range. If you are starting from this point, then yes you need to make a modification to find a way of bidding these hands. As other posters have said, 1M-1NT-2NT needs to show a strong hand (say good17-19) as you really don't want to play in 2NT with a 15-count opposite a 6-count. Just rebid 2 of a minor. It's traditional to bid the lowest 3-card minor with 5332 hands not strong enough for 2NT, but it's probably better to agree to rebid 2♣ even when the doubleton is in clubs. Some people have mentioned Gazilli. There's no compulsion to play this; like all conventions it has pluses and minuses.

If you want to play something sound and don't mind playing something quite complicated, then the Kokish system file (see the link provided by Dan in post #2) is worthy of consideration. Eric Kokish is both a fan of the weak NT and one of the world's leading bidding theorists.

If you are opening 1♦ on some 15-17 balanced hands then you should not play 1♦-2♣ as game forcing. 1♦-1NT is up to a poor 9-count. 1♦-2♣ is enough to force to game opposite a balanced 15-count; just play Acol style rebids after that.

After 1M-2m and 1♠-2♥ forcing to game, all sorts of rebid structures are possible. If you prefer a natural structure, then Opener's rebids can be similar to Acol with 2NT being 15+ balanced.