[Badmonster]

I've heard many players that I respect discuss why they prefer nmf. For one thing I've heard that checkback reveals too much to the opps. (Not completely sure I understand why) and that you can't get back to the original minor.

Meanwhile a lot of very good players that I also respect and admire prefer checkback. I guess I'd just like to better understand the pros and cons of each treatment.

[luke warm]

maybe roland will read and answer this, he feels even more strongly about it than i do... of the two treatments, imo it isn't even close... 2 way ckback is far superior to nmf (again, in my opinion only)... as far as getting back to the original minor, that's only true if the opening is 1c, but having a way to sign off in 2d or show invitational hands outweighs this one drawback, to me... why play stayman, you lose the 2c bid? every treatment gains somewhere and loses other places

[FrancesHinden]

Just my hypothesis:
When you play a method for a while you get to understand it better, and to get the biggest benefit out of it. All artificial methods only realise their full potential when the possible continuations and inferences have been fully worked out.

That tends to mean that people prefer the methods they have played, and thought about, and worked on over methods that they have only read about. (Obviously there are exceptions or no-one would ever change the way they play, but this is the default position.)

NMF is almost unknown here in England, and I've never come across people playing it in European tournaments although I'm sure some do. Various forms of two-way checkback and/or transfers are popular. So when someone comes across this sequence for the first time, they will often play what their partner is used to, or their friends suggest, and these methods spread.

NMF is, I believe, pretty much the default in ACBL-land and the same applies: when a group of people understand and know the method well they will explain it to their newly-acquired friends and partners and it also spreads.

It's mainly at the interface of different bidding cultures - here online - that more people start to make conscious decisions over which of competing methods to play.

I'm prepared to believe that both approaches work, but of course the methods I play are the best!

[luke warm]

here's a hand wayne posted on another thread:

Scoring: IMP

---

playing ckback this is an easy 1h : 1s : 1nt : 2c : 2d : 2nt pass (or just pass 1nt, which is very possible)

[han]

I have never heard anybody claim that nmf is better than 2-way checkback. Sure, it may be easier to remember (which should not be discarded), but better I have never heard. Could you explain the arguments for nmf?

[Walddk]

luke warm, on Jul 3 2006, 06:41 PM, said:

maybe roland will read and answer this, he feels even more strongly about it than i do

Yes, I strongly believe that two-way checkback Stayman is superior to NMF (also Roudinesco for that matter). There is nothing you can't do that NMF can, but there is plenty you can do which NMF doesn't allow.

The one drawback is that you can't sign off in 2♣, but you can sign off in 2♦ whether the opening is 1♣ or 1♦.

1♣ - 1♠
1N - 2♣
2♦ - p

where 2♦ is forced.

However, if you feel more comfortable with NMF, then play that. I am not saying it's bad, and I'm prepared to play it if my partner insists, but that doesn't change my view. Two-way cb Stayman is better.

NMF is third on my list after Roudi.

Roland

[Badmonster]

Hannie, on Jul 3 2006, 12:14 PM, said:

I have never heard anybody claim that nmf is better than 2-way checkback. Sure, it may be easier to remember (which should not be discarded), but better I have never heard. Could you explain the arguments for nmf?

I have heard that checkback gives the opps too much information. But this is simplistic. I cannot really explain the arguments for either, because I don't understand it well enough yet. Really, I'm hoping someone can explain it to me.

[keylime]

I wholeheartedly agree with Roland. Playing 2 way CBS allows you a greater description of weak/invite hands than NMF. I loathe NMF so much it's about on the level of Gerber put it that way.

A great example are pairs (like in my local p'ship) that use weak/invite Flannery over their minor openings. With CBS you can now bid the long way around so to speak to show these kind of hands. With NMF you have all sorts of problems with these awkward style hands.

Another benefit of CBS is the inferences gained in the auction. You can now stop at 2M knowing that the hands don't mesh very well at all. Furthermore, using CBS you can now use 2NT call by the CBS bidder as a relay asking for shape if you wanted to get exotic.

All in all, CBS is light-years ahead of NMF. I strongly feel that NMF, along with RKC usage and maybe odd/even carding, are the three most negative treatments that players use in ACBL-land.

[cherdano]

luke warm, on Jul 3 2006, 07:13 PM, said:

here's a hand wayne posted on another thread:

Scoring: IMP

---

playing ckback this is an easy 1h : 1s : 1nt : 2c : 2d : 2nt pass (or just pass 1nt, which is very possible)

Jimmy, this hand doesn't illustrate your point very well. Not playing checkback, the bidding would go 1H-1S-1N-2N-P. WTP?

[Walddk]

The best 2-w cb feature is the 2♦ relay. Now you are in a game forcing situation at a low level and you have all the room in the world to explore. Opener can show any shape no higher than 3♦.

Roland

[kenberg]

I would be delighted to see a well worked out 2 way checkback system and a well worked out nmf system. I play nmf. For sorting out the majors, it's fine as near as I can tell. But more advanced forms can in principle help with unbalanced hands that have a minor and major. Basically I don't know how to do this in a way that I feel certain I can control. Here is the problem in nmf: After 1C-1S-1NT, the bid of 2D checks back for a major fit, and shows invitational values. A partner with two spades, four hearts, and the upper limit of his NT rebid might well choose to rebid 3H, not 2H. If I hold a strong hand with five spades and five diamonds, I won't be happy with this development. One could solve this by requiring that even with a max, opener bids only 2H. Since responder will bid again if he lacks four hearts, and will perhaps be happy enough to bid 3H with just the bare minimum for his 2D ask, this may work out but it does lose the clarity of 3H with hearts and a max, 2H with hearts but less than a max.

It is, I think, consistent with the poster's original intent to ask how advanced nmf folks do this, and how it is handled in 2 way checkback.

There are many things that I and others often don't bother to work out because the problem hands rarely arise. This nmf business is one of them. I play with one partner once or twice a week here on BBO. We have agreed to play nmf, with no clarifying discussion. Of course there are evil things lurking, and no doubt one will jump out sometime, but so far it (nmf, at least) has gone smoothly.

Ken

Possibly Roland's post, right above mine, answers the question for the 5-5 M/m?

[P_Marlowe]

luke warm, on Jul 3 2006, 12:13 PM, said:

here's a hand wayne posted on another thread:

Dealer: West Vul: All Scoring: IMP

♠ A76 ♥ K87 ♦ JT86 ♣ QJ4 ♠ QJ8 ♥ QJ543 ♦ K3 ♣ K92 ♠ K953 ♥ 62 ♦ A752 ♣ A87 ♠ T42 ♥ AT9 ♦ Q94 ♣ T653

playing ckback this is an easy 1h : 1s : 1nt : 2c : 2d : 2nt pass (or just pass 1nt, which is very possible)

Not 100% sure what the given auction
shows, but playing NMF or no convention
at all:

1h : 1s : 1nt : 2nt : pass

With kind regards
Marlowe

[P_Marlowe]

keylime, on Jul 3 2006, 12:28 PM, said:

<snip>
All in all, CBS is light-years ahead of NMF. I strongly feel that NMF, along with RKC usage and maybe odd/even carding, are the three most negative treatments that players use in ACBL-land.
<snip>

A bid harsh, dont you think?

2-way stayman, or relais transfer, or...
are certainly more powerful conventions
than NMF, but NMF will solve 80-90% of
the hands in question.
Assuming, that you play 100-200 boards
a week ( I play a lot less), simply ask
yourself the question, on how many boards
it will matter for most members in ACBL land.
So for people, who work regular and play
bridge for fun / pleasure, NMF is sufficient.

With kind regards
Marlowe

[mike777]

Walddk, on Jul 3 2006, 12:16 PM, said:

luke warm, on Jul 3 2006, 06:41 PM, said:

maybe roland will read and answer this, he feels even more strongly about it than i do

Yes, I strongly believe that two-way checkback Stayman is superior to NMF (also Roudinesco for that matter). There is nothing you can't do that NMF can, but there is plenty you can do which NMF doesn't allow.

The one drawback is that you can't sign off in 2♣, but you can sign off in 2♦ whether the opening is 1♣ or 1♦.

1♣ - 1♠
1N - 2♣
2♦ - p

where 2♦ is forced.

However, if you feel more comfortable with NMF, then play that. I am not saying it's bad, and I'm prepared to play it if my partner insists, but that doesn't change my view. Two-way cb Stayman is better.

NMF is third on my list after Roudi.

Roland

Let us not confuse 2 way checkback and xyz they are not the same.

2c does not force 2d in 2 way checkback.
Heck many play a xyz version where 2c does not always force 2d. They prefer to have partner show 3 card major suit support as the first priority .

[Walddk]

mike777, on Jul 3 2006, 08:36 PM, said:

Let us not confuse 2 way checkback and xyz they are not the same.

2c does not force 2d in 2 way checkback.

I am sorry, but you are wrong. Playing two-way checkback Stayman, 2♣ is a puppet to 2♦, either to play (rare) or followed by an invitational bid. Opener has no choice; he must bid 2♦.

If you don't believe me, then perhaps you believe Kit Woolsey. Have a look:

http://www.gg.caltec...ycheckback.html

This site will also give others an excellent opportunity to see what's involved if you decide to play two-way checkback Stayman.

Roland

[Elianna]

Walddk, on Jul 3 2006, 11:02 AM, said:

http://www.gg.caltec...ycheckback.html

I don't really see the difference between this and 2way NMF. Is there a difference?

Also, I know that the checkback taught by one of our local teachers is different than this. When people say "checkback" in the US, do they usually mean 2way? That was my interpretation, but apparantly not the interpretation of this teacher, and several others.

[Badmonster]

Thank you for the link, Roland.

[1eyedjack]

Heh, I was waiting for someone to clarify just what 2-way checkback IS. Thanks for that. It is not a million miles from what I developed independently with pard, but there are some differences:

I use 1x-1y-1N-2D as the starting point on all invitational sequences (itself being a forcing bid), and on balanced slam tries (where opener's rebid is likely to be of equal value). Opener assumes a game invite until clarified, and can freely bid at the 3 level with a max but will attempt where possible (opposite a non-passed hand) to protect against the possible slam try.

Then all other sequences deny a game try, being either weak or GF. 2C is a puppet to 2D (not refusable), which might be to play in 2D (or even to play in 2S after another 2H puppet), but otherwise is GF with at least 5 cards in responder's first suit (happily the number of sequences up to 3N just manage to get the hand patterns in).

2H is weak and natural, to play or convert (if it shows a second suit).

2S+ are all GF distributional hands denying a 5th card in responder's first suit (happily there are just about the right number of sequences up to 3N to show these hand types). Oh, but with a weak hand to play in Clubs you start with 2N (over the 1N) puppet to 3C which you then pass.

Don't know how that compares with "2-way checkback" in which 2C puppet to 2D is the start of an invitational sequence. Perhaps there is not a whole heap of difference.

[keylime]

P_Marlowe, on Jul 3 2006, 01:22 PM, said:

keylime, on Jul 3 2006, 12:28 PM, said:

<snip>
All in all, CBS is light-years ahead of NMF. I strongly feel that NMF, along with RKC usage and maybe odd/even carding, are the three most negative treatments that players use in ACBL-land.
<snip>

A bid harsh, dont you think?

2-way stayman, or relais transfer, or...
are certainly more powerful conventions
than NMF, but NMF will solve 80-90% of
the hands in question.
Assuming, that you play 100-200 boards
a week ( I play a lot less), simply ask
yourself the question, on how many boards
it will matter for most members in ACBL land.
So for people, who work regular and play
bridge for fun / pleasure, NMF is sufficient.

With kind regards
Marlowe

Nothing harsh about it. I've seen my fair share of NMF foulups because players forget to discuss the follow-ons with any sense of detail after the bid is made.

[luke warm]

P_Marlowe, on Jul 3 2006, 01:15 PM, said:

Not 100% sure what the given auction shows, but playing NMF or no convention at all:

1h : 1s : 1nt : 2nt : pass

With kind regards
Marlowe

you and arend are right, my point (hazy as it was) was to show that any minor suit bid, playing nmf, is game forcing.. it's true that the given hand isn't a good example

the link roland gave is excellent, but his write-up on his 2/1 page is far better, imo...

go here: roland's write up and just register.. then click 'lessons' and, on bottom right, 'all articles'... then scroll to the 2 way article... great write up and shows, imo, the power of the convention