[paulg]

Personally it was the disclosure aspects that I found more concerning than the 'two systems'. Currently your partner is alerting 1NT because you may have a singleton, when it seems you never will.

When it comes to differing styles when opening one notrump with 5-card major or not, then again I think disclosure is key. I would take the same view of the opening bid in Acol with the 4M4m hands, even though I do think these are different systems

[pran]

 Zelandakh, on 2012-September-10, 07:43, said:

Well yes and no. The methods over 1NT are essentially SAYC and pay no attention to the possivble 44(41) hand whatsoever. On the other hand the methods after 1♦ specifically cater to the 4441 hand by including a 2♦ rebid after 1♦ - 2♣ as a 1 round force which could have only 4 diamonds. The actual theoretical meaings of all bids are identical, it is only that there are 2 possible ways of bidding these hands. There are inferences from the radical difference in style which the opps are entitled to. What I was getting at is where a difference in style crosses over from that to two partners actually playing different systems. Note that the example could just as easily be the choice of opening the major or the minor in a 4432 hand in Acol, or of opening 1M or 1NT with a 5332 hand within range. If 2 options are available and one partner always chooses one while the other always chooses the other, then what is the criteria for this becoming 2 different systems?

HUH?

Are we discussing defences over 1NT?

I thought we were discussing variations on the agreements for the 1NT opening bid itself?

(The difference is very important!)

[Zelandakh]

 pran, on 2012-September-10, 08:53, said:

Are we discussing defences over 1NT?

For "methods over 1NT", read "methods after partner opens 1NT and next hand passes". I assume this is the phrase that caused the misunderstanding.

[blackshoe]

 Zelandakh, on 2012-September-10, 07:43, said:

If 2 options are available and one partner always chooses one while the other always chooses the other, then what is are the criteria for this becoming 2 different systems?

FYP.
There are no stated criteria, afaik. It's a matter for TD judgment.

[barmar]

 Zelandakh, on 2012-September-10, 02:02, said:

I think David is right here and here's a simple example to show it. Suppose I open 4NT Specific Ace Ask. I cannot remember the last time I did this but it is more than a year ago. But if I have the agreement with partner that this is the meaning then it is expected and should be disclosed. The same is true for any other rare tendencies partner might have - if I know partner's style well enough to expect them then they are surely disclosable.

Related != perfect correlation

[bluejak]

Style is a bit tricky. In general it is alright to have system in such a way that one player is much more aggressive, one player likes to bid in a more accurate type of approach and so on. Possible 4441s are interesting - and it is not a disclosure issue because you can always disclose style, in fact you should. So a description that 1NT can be 4441, tempered with the comment that one player likes to do this but the other very rarely does, sounds legitimate to me.