[hrothgar]

akhare, on 2012-January-06, 14:35, said:

I think this is important point to consider as well in defining the SP responses to 1♣.

IMO, it's possible to straddle the "best of both worlds" in a scheme that uses a two way 1♦ response and allocating *some* immediate responses for SP hands with the majors.

Once again, please don't underestimate the value of have a forcing pass established following

1♣ - (P) - 1♦

For whatever reason, people like walking into that auction

"The opened 1♣! They have a strong hand and showed nothing about shape! Just wait until partner bids 2♠"
"Damn, partner passed!"
"What's this!!! They just bid 1♦ its another strong bid that shows nothing about shape! I can't bid spades, but I can still bid 2♥ and screw them and their precious little relays"
"OOH!!! A red card, I am so scared!"
"Maybe -800 won't score up so bad... And they missed their cold 3NT!!!"

[akhare]

hrothgar, on 2012-January-06, 14:47, said:

Once again, please don't underestimate the value of have a forcing pass established following

1♣ - (P) - 1♦

For whatever reason, people like walking into that auction

Absolutely agree with you regarding the value of FP that's established following a GF response. There's no doubt that one of the tradeoffs of playing a two way 1♦ is the loss of the FP.

The question is whether this loss can is offset by (subjective) gains elsewhere. For the design goals I had in mind, the answer seems like a yes, but as always, the real proof lies in actually trying it out...

[whereagles]

Using 1C-1D as GF is certainly playable, but it leaves both RHO with an easy butt-in at low level when both hands have shown no distrubution.

For that reason would prefer a GF response to show a suit.

[straube]

An important thing that I like about 1S as DN is that it brings this hand into the auction. Responder may not have high cards, but he can have distribution. Say the auction goes...

1C P 1S (2D)
P P ?

It's nice for responder to be able to compete 2H with xx Qxxxx xx xxxx without promising much. Yes, it may be wrong, but we rate to have half the deck and letting them play 2D may also be wrong.

Or responder could have xxxx xxx x xxxxx and then he might double. Opener ought not pass unless he sees a set by his own hand, but he just might have that. Opener's own double would also be takeout, so whose to say he can't have a primary diamond suit that has no bid over the overcall? On more days of the week, he'll have something like AKJx KQx Kxxx Qx and will bid 2S. I don't think there's a way to compete here if responder hasn't already limited his hand.

My example hands might be marginal for whether responder wants to act, but one could come up with something more clear-cut and the principle remains the same.

[hrothgar]

whereagles, on 2012-January-06, 15:27, said:

Using 1C-1D as GF is certainly playable, but it leaves both RHO with an easy butt-in at low level when both hands have shown no distrubution.

For that reason would prefer a GF response to show a suit.

As I recall, we tended to get pretty good scores when folks were dumb enough to butt in after 1♣ - (P) - 1♦

(Not as good as when they'd butt in after out 2♦ or 2♥ openings, but we'd still be in a nice position to hammer them...)

[akhare]

straube, on 2012-January-06, 15:57, said:

An important thing that I like about 1S as DN is that it brings this hand into the auction. Responder may not have high cards, but he can have distribution. Say the auction goes...

1C P 1S (2D)
P P ?

This is a valid point, but I think one would be hard pressed to justify this on the basis of frequency. I can't seem to recall holding a single DN hand that took action after LHO's overcall after 1♣ - 1♠ - (blah) - P - (P).

[whereagles]

hrothgar, on 2012-January-06, 17:01, said:

As I recall, we tended to get pretty good scores when folks were dumb enough to butt in after 1♣ - (P) - 1♦

You're bound to have good scores when people do dumb things LOL

[Zelandakh]

I do not think 1S as a DN is unsound. You get some plusses and some minuses. That said I am not yet convinced it is optimal. As you know I have a strong club system where the opening 1C bid can be made with a flat 15 which puts me in a similar situation to you on the percentage of hands in the GF/SP/DN ranges. For me 1D as 0-8 works just fine after which I just ditch relays and use the extra space to split hand types up tightly enough to make natural bidding work. I am sure I lose something by not being able to relay SPs, I am just not convinced it is enough.

When I was designing the system I did consider a split range response structure such as Adam uses. I do not really see any problem with it as "DN or GF" is no more difficult to use, and arguably simpler, than the traditional "DN or SP". That said, it did not fit the way my system is built so I did not pursue it. It makes more sense if you (almost) always relay after a positive (I only relay with 18+) since now you really are not losing very much. I prefer this in general to the 1S DN but you always have to play-test for a specific system to see which works in context.