[aguahombre]

There are so many reasons that on the auction:
1C-1D
1N-? 2c (or 2D) should not be part of any checkback system, that I can't say them all.

Of course, I am speaking from an original assumption where 1D denies a major unless G.F. With game-force responder can rebid quite naturally ---opener could easily have even two 4-card majors, but it doesn't take any gadget to find that.

[Cthulhu D]

 aguahombre, on 2012-March-18, 20:34, said:

There are so many reasons that on the auction:
1C-1D
1N-? 2c (or 2D) should not be part of any checkback system, that I can't say them all.

Of course, I am speaking from an original assumption where 1D denies a major unless G.F. With game-force responder can rebid quite naturally ---opener could easily have even two 4-card majors, but it doesn't take any gadget to find that.

What this auction is to walsh, I'm pretty sure it's the same as the auction 1C!-1D!-1S is to transfer Walsh. A hopeless situation to use XYZ as the unbalanced nature of opener makes things very tricky.

[Zelandakh]

I think the relative merits of the two is partly dependant on the base system. If you play that all balanced hands outside of NT range open 1♣ then using NMF here is extremely unattractive. On the other hand, if you play that the 1♣ opening promises 4 then NMF starts to look reasonably good. The trade-off depends on how important it is to be able to show a weak hand with fit for Opener's 1♣ call in comparison with the constructive hands that are more efficient when you give up a natural 2♣. From what I have seen though, the majority of 5 card major players now use 2-way checkback so the comparison is really somewhat obsolete.

[Statto]

 aguahombre, on 2012-March-18, 20:34, said:

Of course, I am speaking from an original assumption where 1D denies a major unless G.F. ...

It depends on style as Zel pointed out. With 2 4-card suits I would bid up the line, so 1♦ would probably deny a 5-card major (but not a 4-card major), though may be 5-6 etc. Would opener skip a 4-card major to bid 1NT? It seems to be a popular style with WNT to show the extra strength...

[gordontd]

 blackshoe, on 2012-March-18, 07:24, said:

4. Two way Checkback Stayman, which works just like two way Stayman over an opening 1NT. IOW, 2♣ is invitational, and 2♦ is GF.

The important bit you've missed out is that 2♣ forces 2♦ (which can be passed), and then subsequent bids are invitational.

[MrAce]

 aguahombre, on 2012-March-18, 20:34, said:

There are so many reasons that on the auction:
1C-1D
1N-? 2c (or 2D) should not be part of any checkback system, that I can't say them all.

Of course, I am speaking from an original assumption where 1D denies a major unless G.F. With game-force responder can rebid quite naturally ---opener could easily have even two 4-card majors, but it doesn't take any gadget to find that.

Yes, you can chose to bid naturally if you are by passing ♦ suit with less than GF hands. Which is also the method that i use.

But still you need to use check back. For example;

1♣--1♦
1NT How will you set trumps ♦ or ♣ and start a forcing auction without using 2♣ ? Because the method you suggest is obviously clear when you have a side 4 card major, pd will understand you have a GF hand since you didnt skip ♦ suit, but what if you dont have a side 4 card M ? You may use 3m as forcing but then how will you make game invitation ?

Also, there are 2 ways to find 4-4 major fits in this auction

a-You ask via check back ( for the hands which you only want to play game, balanced hands)

b-You bid naturally as you suggested. ( i used both of them b4 i started 2 way nmf, this one showed 6-4 hands and unbalanced with a stiff or void for slam purposes, while as i said other one was with balanced hands and only for game )

[Statto]

 MrAce, on 2012-March-20, 05:06, said:

Yes, you can chose to bid naturally if you are by passing ♦ ...

If I am passing ♦ I'm pretty sure I won't be feeling natural, I'd see a doctor.

Sorry

[MrAce]

 Statto, on 2012-March-20, 05:33, said:

If I am passing ♦ I'm pretty sure I won't be feeling natural, I'd see a doctor.

Sorry

[aguahombre]

 MrAce, on 2012-March-20, 05:06, said:

But still you need to use check back. For example;

1♣--1♦
1NT How will you set trumps ♦ or ♣ and start a forcing auction without using 2♣ ?

Since you already stated in the first sentence that we still need to use check back, perhaps the question in the 2nd sentence was made to be rhetorical. But, I will answer anyway.

Again, so much depends on context of all our agreements which might make the problem non-existent. However, for those who don't have our agreements and don't want to use 2C ---they can make a semi-natural major suit rebid, then establish the minor on the next round...creating their G.F. slam probe.

Now for why we don't have the problem:

It is only the responding hands which are slammish opposite a 1NT rebid that are of concern here.

Slammish hands with long clubs start with inverted club raise (5+ clubs)
Slammish hands with long diamonds or seriously two-suited (5+5+) minor suit hands start with 2♦. 2D/1C is the 2-level jump shift which we don't use as weak. Continuations are pretty much as Mike Lawrence has written up.

I feel like a broken record harping on context, and why some of our agreements which are not mainstream are workable, rather than the negative terms others use to describe them. Conversely, I don't badmouth the mainstream methods because they involve a different context from ours ---and might be the best alternative to revising parts of their system, for those pairs.

[Zelandakh]

 MrAce, on 2012-March-20, 05:06, said:

1♣--1♦
1NT How will you set trumps ♦ or ♣ and start a forcing auction without using 2♣ ?

You could, of course, simply define a 3♥ rebid as a slam try in clubs and a 3♠ rebid as a slam try in diamonds. Or you could define 2♥ as "hearts or slammy in a minor" and then use some artificial continuations to sort it out.

[MrAce]

 Zelandakh, on 2012-March-20, 08:19, said:

You could, of course, simply define a 3♥ rebid as a slam try in clubs and a 3♠ rebid as a slam try in diamonds. Or you could define 2♥ as "hearts or slammy in a minor" and then use some artificial continuations to sort it out.

Yes Zel, i could, but does it worth to put artificial meanings to more than 1 bid, just to keep our ability to play 2♣ ? Just so we can use 2♣ as natural ? And as i said earlier in the thread, and saying again for this auction ;

1♣--1♦
1NT--2♣ (to play, retreat from NT)

How often do we really expect this type of hand to come and how often are we expecting our opponents to sell it out to us ?

[655321]

 aguahombre, on 2012-March-18, 20:34, said:

There are so many reasons that on the auction:
1C-1D
1N-? 2c (or 2D) should not be part of any checkback system, that I can't say them all.

Of course, I am speaking from an original assumption where 1D denies a major unless G.F. With game-force responder can rebid quite naturally ---opener could easily have even two 4-card majors, but it doesn't take any gadget to find that.

Presumably this controversial claim was a typo for "Aquawoman and I happen not to use checkback in this auction."

[nige1]

IMO Marvin is right. For your amusement, here is the variation that I play. After say...:
1♥- 1♠ -
1N - 2♣ = Modified Crowhurst (so-named because Eric Crowhurst invented check-back)
Then...

• 2♦ = MIn neither 3 ♠ nor 5 ♥,
• 2♥ = Min with 5 ♥.. May have 3 ♠.
• 2♠ = Min with 3 ♠. (After minimum replies, responder's new suit and 3-level bids are forcing).
• 2N = Max flat (Responder continues naturally)
• 3♣ = Max off-shape 1534 e..g ♠ Q ♥ Qxxxx ♦ AQx ♣ AQJx (assuming 1N rebid = 15-17).
• 3♦ = Max off-shape 1543.
• 3♥ = max off-shape 1633.e.g. ♠ A ♥ Jxxxxx ♦ AQJ ♣ AJx
• 3♠ = max off-shape 1444.
• 3N = Max 2533 (only if responder is unlimited)