[Knurdler]

We play 3C after 1 minor 1 major 2NT (no interference) as checkback asking opener if they have 3 card support for responders major or 4 of the other major.
I think the openers bid of responders major is fairly standard as showing 3 card support only and openers bid of the other major as showing 4 of it only.
We use 3D by opener as denying both and 3NT as having both but I have just discovered and that some play the other way round: 3D as having both and 3NT as denying both.

Which use of 3D / 3NT is more common and is one theoretically better?
Can or should checkback apply after interference from fourth seat?

Thanks

[mike777]

I prefer Wolff and this follow up, hope you find this helpful.


After 1m-1Y-2N

i)3C= Wolff signoff- relay to 3D

(1) 3M to play

(2) 3OM= slammish in om(or D after 1C-1D-2N)

(4) 4m= very strong slam try in m

ii) 3D= checkback- opener bids 4 card major 1st-??
iii) 3M = 6 card suit slammish
iv) 3OM= 5-5 or 6-5

This post has been edited by mike777: 2025-October-20, 09:03

[DavidKok]

There are several different schemes. A common one is Wolff signoff/relay, but it is sufficiently different from Checkback that this'd be a significant change.
Personally I play Checkback, but my scheme is different from either one you proposed. I play that 3♦ denies both, and with both you bid 3♥ (the cheaper one). On the auction 1♣-1♠; 2NT-3♣; 3♥-3NT; ? you correct to 4♠ - opener would not have asked without interest in your 3 card spade suit.
My 2NT rebids are somewhat different than most, playing a balanced club with Dutch Doubleton. I think in standard it's more valuable to have a way to sign off at the three level. There is one more implication to play in mind: I play 1m-2M as weak (approximately 4-8) with 6(+) cards. This means that, on 1m-1M; 2NT-?, if responder has 6(+)M they are worth a game force. In addition, if they do not bid game, they have a slam try. It is very valuable to keep track of negative inferences like this, if your system contains them.

[P_Marlowe]

Hi,

I think 3D showing both has the advantage, that responder can start a
slam auction on the 3 level.
If you have neither, the endcontract to play is 3NT, you bid it.

In case it matters, I would assume NMF playing with a stranger, i.e.
there is no bid to show both, the bid to show neither is 3NT.

With kind regards
Marlowe

PS: In my reg. partnership we play a weak NT and a wide range NT rebid,
i.e. I dont have this problem, I have other.

PSS: Give an auction with interference, but after an overcall, opener usually
showes 3 card support by making a SuppX, or he makes a T/O, if responders
suit is diamonds, i.e. showing bith is no longer a need.

PSSS: Would it be possible to avoid CAPS LETTERS in the description.

[pescetom]

P_Marlowe, on 2025-October-20, 12:20, said:

PSSS: Would it be possible to avoid CAPS LETTERS in the description.

Not only possible when one creates the thread, but also later by editing the OP (at least on a PC).
"Checkback after 1m-1M-2NT" might be a better title too (many of us play a checkback by Opener over a 1M-2NT limit raise).