[Mbodell]

I agree that 1nt should be the weaker option and 1♠ the stronger. At least unless 1♠ is split range and you need the weaker option further from the split range.

[Zelandakh]

rogerclee, on 2011-December-19, 01:55, said:

1S = 11-13 balanced
1N = 14-16 balanced

I have some questions though.

2) Would you rather play 1S is weaker or stronger than 1N?

Zelandakh, on 2011-December-19, 03:31, said:

2. I would prefer 1NT weaker for maximum pressure.

hrothgar, on 2011-December-22, 11:57, said:

Have you considered swapping the 1♠ and 1NT openings?

Yes, I think this was considered.

[twoshy]

A pair at the local club have played this base for a few years. I don't know if they picked it up from somewhere else, though. (New or highly modified systems crop up all the time in NZ.) Anyway, the only bit of their system I've paid much attention to is the 1♠ opening.

They play 1♠ as 12-14 and 1NT as 15-17. The argument seems to be that it is more important to right-side the strong(er) NT on a partscore hand, since the balance of HCP is more heavily weighted towards opener. Granted, it is more likely for the partnership to want to play 1NT opposite a weak (or 11-13) NT, but wrong-siding 1NT will not be as bad when responder has 6+ HCP. There is also much less information available to the defense compared to 1NT-P. Minimum responding hands can introduce a bit of randomness by passing 1♠, too. If 1♠ is doubled to show a normal penalty double of 1NT, then there are more ways to find the correct spot; the weaker range is more likely to get smashed.

One of the disadvantages with opening 1♠ is that the opponents have an extra way to intervene via the 1NT overcall. (Assigning meanings to pass-then-act is too dangerous when 1♠ is often swished.) Also, the opponents can act after passing with marginal hands should 1NT come back to them, although I'm sure this isn't a big disadvantage. It is neat to be able to bid 1♠ P 1NT P P 2m natural, though.

The main point of all this is that opening 1♠ has more to gain when the hand is weaker.

[hrothgar]

Hey there

It probably comes as no great surprise, but I prefer the "standard" MOSCITO opening structure to what you're proposing.

For the purpose of this analysis, I am going to assume a slight modification to my preferred MOSCITO variant.
The "new" structure opens all balanced 11+ <--> 14 HCP with 1NT. Therefore the 1D/1H opening promise an unbalanced hand.
I'm am then going to compare the various opening bids.

1♦ /1♥ are a "wash". The bids essentially promise the same hand type.
1NT also seems pretty much the same. I'd be hard pressed to argue that an 11+ - 14 NT is intrinsically better or worse than a 14 - 16 NT.

2♣: First big difference. The MOSCITO 2♣ explicitly promises 6+ Clubs and denies 4 Diamonds. (You also have the option of opening 2♣ with an unbiddable 4 card major)
I'd argue that you're better positioned after the MOSCITO 2♣ opening.

2♦: Another bid difference/ MOSCITO uses 1♠ for this hand type. Here once again, I prefer the MOSCITO treatment.
You can play 2♣ when its right and you have MUCH more bidding space to investigate 5-3 major suit fits with invitational hands.
Moreover, 2♦ is a free bid playing MOSCITO. You can use this for whatever preempt you want.

1♣: You're 1♣ opening is significantly stronger than MOSCITO.
There are definite advantages to this style. You'll be better situated in competition. You can use a simpler response structure over 1♣ (you don't need to worry about the whole semi-positive / double negative debate)

1S = 11-13 balanced: Not enough experience with this opening to comment

If I were going to summary pros / cons I think that MOSCITO wins out.

You are (basically) trading off a stronger 1♣ opening and your "balanced Spade" against

Having a 2♦ bid available to show some kind of preempt
Opening 1♠ with two suited hands with the minors or 6+ Diamonds
A 2♣ opening that promises 6+ Clubs