[RuflRabbit]

I'm interested in gathering suggestions for methods when the opponents interfere with a natural 3-level suit call over our 2NT (20-21) opener.

If it matters, if the opps interfere at the 3-level over our 1NT (15-17) openers, we play negative doubles and Texas transfers through 4♣.

Thanks for your thoughts!

[pescetom]

It doesn't happen often, nor is it much discussed:
previous discussion

If you are not playing at high level I would just maintain your 1NT methods with the modification that double or redouble by opener are for penalty.

[dsLawsd]

Sounds right. The main thing to try and agree on is what a pass means. Does 3 NT show a full or partial stopper? Fun stuff, eh?

[RuflRabbit]

dsLawsd, on 2019-October-11, 23:48, said:

Sounds right. The main thing to try and agree on is what a pass means. Does 3 NT show a full or partial stopper? Fun stuff, eh?

Almost makes you want to interfere more with their 2NT.

[P0STM0RTEM]

Pescetom's link to Bob's suggestion about Pass being Forcing seems the way to go. Then opener I assume would overcall any 5 card suit at the 3-level and double failing that thus allowing a Penalty Pass conversion by responder.

I'll take the bidding tree one step further:
2NT 3 X ?

Pass is Forcing
Double generally without a Quality 5+ long suit
Pass = Penalty Pass conversion
Next Suit Up = To Play (no ability to transfer into it)
Higher 3-level Suit = Invitational to 3N or 4M
3NT = Option to play w/ invite in what would have be next suit
3-level shows Quality 5+ long suit

Double negative (up to 4♥)

3♦, 3♥ transfer to suit above

3♠ asks for stopper in enemy shown suit

3NT sign-off

4♣ Gerber

4♦, 4♥ transfer to major above, or splinter slam try if next higher suit is enemy suit

4♠ quantitative (16+-17)

4NT quantitative (15 to 16-)

[pescetom]

P0STM0RTEM, on 2019-October-12, 11:18, said:

Pescetom's link to Bob's suggestion about Pass being Forcing seems the way to go. Then opener I assume would overcall any 5 card suit at the 3-level and double failing that thus allowing a Penalty Pass conversion by responder.

I'll take the bidding tree one step further:
2NT 3 X ?

Pass is Forcing
Double generally without a Quality 5+ long suit
Pass = Penalty Pass conversion
Next Suit Up = To Play (no ability to transfer into it)
Higher 3-level Suit = Invitational to 3N or 4M
3NT = Option to play w/ invite in what would have be next suit
3-level shows Quality 5+ long suit

Double negative (up to 4♥)

3♦, 3♥ transfer to suit above

3♠ asks for stopper in enemy shown suit

3NT sign-off

4♣ Gerber

4♦, 4♥ transfer to major above, or splinter slam try if next higher suit is enemy suit

4♠ quantitative (16+-17)

4NT quantitative (15 to 16-)

Looks like an effective scheme.
Out of interest, how would you handle 2 or 3 level interference over strong 2♣ ?

[Zelandakh]

pescetom, on 2019-October-12, 15:08, said:

Looks like an effective scheme.
Out of interest, how would you handle 2 or 3 level interference over strong 2♣ ?

Fairly standard over a strong 2♣ opener is for Pass to show values and Double (or Redouble) to be a negative response, with suit calls being natural and positive similar to an uncontested auction. I think less standard is a 2NT response after interference. That is generally just played the same way as in an uncontested auction, whether natural or artificial, but another very logical usage would be a positive in the highest-ranking preempted suit, which can sometimes save a lot of space (eg after 2♣ - (2♠), 2NT instead of 3♥ as a positive with 5+ hearts gives 8 times as many possible auctions below the 3NT level, which is a considerable increase). Against that, many experts believe that the ability to split up the ranges of their balanced and semi-balanced positive hands is key to good slam bidding and that is certainly lost if all such hands have to start with a pass.

[pescetom]

Zelandakh, on 2019-October-22, 04:00, said:

Fairly standard over a strong 2♣ opener is for Pass to show values and Double (or Redouble) to be a negative response, with suit calls being natural and positive similar to an uncontested auction. I think less standard is a 2NT response after interference. That is generally just played the same way as in an uncontested auction, whether natural or artificial, but another very logical usage would be a positive in the highest-ranking preempted suit, which can sometimes save a lot of space (eg after 2♣ - (2♠), 2NT instead of 3♥ as a positive with 5+ hearts gives 8 times as many possible auctions below the 3NT level, which is a considerable increase). Against that, many experts believe that the ability to split up the ranges of their balanced and semi-balanced positive hands is key to good slam bidding and that is certainly lost if all such hands have to start with a pass.

Thanks. That's pretty much what we do at present, with 2NT retaining our usual meaning of both minors - I agree it would make more sense for it to become the highest-ranking preempted suit. We have multiple precise ranges for opener's NT after 2♣ so we leave any quantitative decision to responder.