[Siegmund]

The two I have been happiest with have been CRASH(or CHASM or SCUM, to make it GCC legal), and "BROOSS" from Kleinman's NT Zone. The latter is useful mostly as being one of the few conventional methods to keep all three of 2D,2H, and 2S natural. (X=clubs, or a two-suiter without clubs, while 2C=C+M.)

I am a big believer in having 2M be natural. Beyond that, I like showing as many hand-types as I can with the cheap overcalls.

Multi-Landy's 2C bid is great for constructive purposes, and is the sort of thing I'd like over a weak notrump, but I think is just too valuable of a bid to give to only one hand pattern in a primarily obstructive auction.

I've wanted to try a system that could distinguish all of the 4-5s from the 5-4s (maybe X=4M5+m, while 2C promises 5M+another, or something) but never found one I liked.

[Zelandakh]

Siegmund, on 2014-February-07, 00:44, said:

I've wanted to try a system that could distinguish all of the 4-5s from the 5-4s (maybe X=4M5+m, while 2C promises 5M+another, or something) but never found one I liked.

There are lots of ways of doing this if you ignore the hands with both minors. You could adapt my method to include natural 2M overcalls and lose the cheap 3-suiters by:

X = hearts + another (2♣ = non-forcing relay for 5 card suit)
2♣ = spades + another (2♦ = non-forcing relay for 5 card suit)
2♦ = open
2M = nat

For the 2♦ overcall, choose one from:

a. nat
b. 5-5 majors
c. minors
d. some 3-suited shapes (qv Sharples)

c would allow you to differentiate all 5-4s from 4-5s but is probably bad in practise due to this being such a low priority hand type.

[helene_t]

Siegmund, on 2014-February-07, 00:44, said:

I've wanted to try a system that could distinguish all of the 4-5s from the 5-4s (maybe X=4M5+m, while 2C promises 5M+another, or something) but never found one I liked.

You might want to try AWM's system ("Meyerson"):

X= major/minor two-seater. Now 2♣ is N/F relay asking for the 5-card suit, while 2♦ asks for the major
2♣=majors

[fromageGB]

Siegmund, on 2014-February-07, 00:44, said:

I've wanted to try a system that could distinguish all of the 4-5s from the 5-4s (maybe X=4M5+m, while 2C promises 5M+another, or something) but never found one I liked.

Don't forget that if you use X or 2♣ for both majors of unspecified lengths, you can easily get the best fit by a direct 2♥/♠ reply being to play with 4 cards or 2+ cards better in advancer's length, while a lower reply asks for doubler to bid his longer. (Numbers on the basis that a 5-2 fit is better than a 4-3 fit, but you would prefer a 4-4 to a 5-3. Or adjust to taste.)

Playing X for both majors gives you a choice of different add-ons:
1) 2♦ asks for longer, while 2♣ says "I hate the majors, pass or correct to 2♦".
2) For a bit of fun, put opener on lead :
2a) If it was a 2nd seat X, 2♣ asks for longer major to be expressed by red suit transfer, 2M = this major
2b) If it was a 4th seat X, then 2♣ asks for longer major to be bid directly, red suit transfer = this major

[fromageGB]

helene_t, on 2014-February-07, 03:44, said:

X= major/minor two-seater. Now 2♣ is N/F relay asking for the 5-card suit, while 2♦ asks for the major
2♣=majors

A 3-seater is better, as it has the advantage that one defender does not have to sit on the knees of the other.

[Trinidad]

The NT defense that is most suitable depends on your aim. If you want to bid constructively and find your side's best contract then pick a constructive convention (As(p/t)ro, Multi-Landy, Cappelletti, etc.). If you want to keep the opponents out of their best paying contract then destructive conventions fit best (DONT, Lionel).

Destructive conventions are characterized by bids that partner can pass: Fast in, fast out. That means that it is difficult for overcaller to show a good hand. The constructive conventions are better suited for that.

Whether you want to bid to your best contract or mess with them depends on quite a few variables:

• Your general approach of the game
  
• The form of scoring
  
• The vulnerability
  
• The strength of the 1NT opening
  
• The strength of the field

Your overcalling style (the hands with which you overcall) and system need to be consistent. If you play DONT then don't be bothered (too much / at all) by HCPs, as long as you have the right distribution. If you play Cappelletti, then don't overcall on lousy hands.

I have seen quite a few pairs who play DONT, but can't get to pass with a nice balanced hand. They will overcall 2♣ (♣ + other suit) on ♠K43 ♥AQ98 ♦K6 ♣KJ74 and end up playing there when the field defends 1NT and takes it down 3. Similarly, I have seen people playing Cappeletti, overcalling 2♣ (any single suiter) on hands like ♠73 ♥K87642 ♦743 ♣94. They get raised to 4♥, doubled and go for a telephone number.

You cannot have it both ways. Choose how constructive / destructive you want to be and choose a convention that fits that style.

Rik

[helene_t]

Trinidad, on 2014-February-07, 07:40, said:

If you want to keep the opponents out of their best paying contract then destructive conventions fit best (DONT, Lionel).

I wouldn't call DONT "destructive". It is not aimed at obstructing the opponents auction. Well, maybe for some pairs it is, but it is not very effective in doing so. With weakish one-suited hands you double 3/4 of the time, with good one-suited hands you double all the time, and with two-suited hands you bit 2♣ half the time. So most of the time you don't take away any bidding space at all.

[Zelandakh]

I would not call Asptro constructive either. It is designed to get in light under the protection of shape and fight for the part score.

[helene_t]

The OP stated 15-17 1NT so constructive bidding should not be a priority.

Still, different methods, even if they are all played in a non-constrictive style, have different objectives.

With DONT we get into the auction with all 1- and 2-suiters and never force ourselves to the 3-level. The disadvantages are that we don't usually get to show our major suit so partner can't compete to the 3-level when it's right. And we don't always find the best (paying) fit.

Landy, ML and the various A**ro variants generally find the major suit fit if we have it but with some two-suiters (and minor one-suiters) we will either not be able to bid at all, or we will have to play at the 3-level.

If you play multi and Muiderberg, a passed hand is unlikely to have a long major suit, so your structure should cater to the 4M5m hands, minor onesuiters, and major two-suiters. So playing ML by a passed hand that could have opened Muiderberg is one of the few things that I find really bad.