[straube]

My 1D (1S) thread was very helpful to our system efforts and I'm looking for feedback on 1D (1H) now. Our 1D is artificial and limited. Responder can't make a simple raise to show some values and he's stuck with no heart stopper and no suit (spades especially) to show.

I think we can't afford both dbl and 1S to show spades (as perhaps can standard). After all, they're our 2 lowest and most important bids.

Rough draft...


1D (1H)
.....dbl- 4+ spades
..........1S-3 spades
...............2m-to play?
...............2H-cue
...............2S-fit
..........1N-denies 3 spades
...............2S-invitational with 6 spades
.....1S-bal (8+) or diamonds or GI+ without a suit or 4-1-4-4
..........1N
...............2C-4-1-4-4
....................2D-diamonds
....................2H-stopper ask
....................2S-4-1-4-4, inv+
....................2N-stopper, GF
.......1N-5 spades, nf
.......2C-clubs, f
.......2D-diamonds, GF
.......2H-6 spades, competitive or GF
.......2S-minors
............2N-asks longer minor
.......2N-GI
.......3m-weak
.......3H-stopper, demands 3N (perhaps Kx or Axx or Kxx)
.......3S-weak
.......3N-to play (perhaps QJxx or KJx)

Suggestions? What sorts of hands ought to pass with heart length? What should opener's rebids mean after a pass?

[straube]

1D (1H)

dbl-4 spades
.....1S-balanced
.....1N-spade shortness
.....2C-minors
.....2D-diamonds
.....2H-good raise
.....2S-bad raise

1S-4+ diamonds
.....1N-naturalish or non-fitting
..........2C-clubs, f
..........2D-diamonds, f
..........2H-stopper ask
..........2S-reverse

1N-4+ clubs, nf

2C-4+ clubs, f

2D-diamonds, weak

2H-6 spades, weak

2S-minors, weak

2N-invite

3m-to play

[straube]

1D (1H)

dbl-4 spades

1S-4+ diamonds (3 with invitational+ strength and lacking four clubs)

1N-5+ spades, forcing
.....2C-takeout of spades
.....2D-diamonds
.....2H-good raise
.....2S-bad raise, possibly doubleton

2C-forcing with 4+ clubs

2D-7-11 other (usually 3 diamonds and 4+ clubs)

2H-weak, six spades

2S-5/4 minors

2N-invitational

3m-weak

Using 1S as diamonds seemed like a big winner (I have looked at hands).

I kind of like that opener gets to play spades since that's so often the occurrence after responder shows five spades. It protects against the lead through opener's hearts. The 2D bid is a stuck bid for when responder wants to compete but doesn't have four diamonds or four spades. It's not the best bid, but I hate to sacrifice 1N for such infrequent hand types. The hands I looked at always wound up in a 4-3 diamond fit or an 8-cd club fit or better, but that obviously doesn't have to happen.

I'm wondering what 1D (1H) dbl P continuations should be. Maybe...


1S-minors or balanced no stopper
1N-stopper
2C-5C and 4H
2D-6D or 5D/4H
2H-good raise
2S-bad raise

[awm]

There are a fair number of hands where responder is balanced without four spades. The structure you've proposed has us bidding 1♠ or 2♦ on these hands, which I think is not so good. The 2♦ bid could easily just get us too high when opener is balanced also (and 1NT is the right spot). The problem with 1♠ (and also with passing on natural 1NT hands with 4♥) is that it allows advancer to get in a spade-showing bid. After 1♦-(1♥) where I hold fewer than four spades, it's actually not that unusual for opponents to have an eight-card spade fit. Bidding 1NT (or 2m) on these hands makes it hard for opponents to find that fit. Also, I have my doubts about your forcing 2♣ bid... what do we do when we have a weakish hand with clubs.

Some questions:

(1) Why is 1♠ showing diamonds better than 1♠ showing clubs? If 1♠ was clubs, you could use 2♣ as your minor-suit takeout, or you could play 2♣ transfer to diamonds. Either of these seems to give you more options to get out at a low level in the minor(s).

(2) Is distinguishing between 4♠ and 5+♠ really worth using up the 1NT bid? Would you be better off with a natural 1NT, or with 1NT as some sort of transfer?

[bluecalm]

I played:
dbl = 4+spades
1♠ transfer to NT or clubs
1NT = natural
2♣ = transfer to diamonds
2♦ = transfer to opponents suit, general gf/stopper ask
2♥ = transfer to 6+spades weak or GF
2♠ = clubs , weak or GF
2NT = natural
3♣/3♦ natural, invitational
3♥ 6+spades, invitational
3♠ tranfer to 3NT
3NT = to play

when playing precision;

We used the same structure over 1D - 1S (the club suit is sometimes lost there but there are other advantages)

[straube]

awm, on 2011-February-19, 14:08, said:

There are a fair number of hands where responder is balanced without four spades. The structure you've proposed has us bidding 1♠ or 2♦ on these hands, which I think is not so good. The 2♦ bid could easily just get us too high when opener is balanced also (and 1NT is the right spot). The problem with 1♠ (and also with passing on natural 1NT hands with 4♥) is that it allows advancer to get in a spade-showing bid. After 1♦-(1♥) where I hold fewer than four spades, it's actually not that unusual for opponents to have an eight-card spade fit. Bidding 1NT (or 2m) on these hands makes it hard for opponents to find that fit. Also, I have my doubts about your forcing 2♣ bid... what do we do when we have a weakish hand with clubs.

Some questions:

(1) Why is 1♠ showing diamonds better than 1♠ showing clubs? If 1♠ was clubs, you could use 2♣ as your minor-suit takeout, or you could play 2♣ transfer to diamonds. Either of these seems to give you more options to get out at a low level in the minor(s).

(2) Is distinguishing between 4♠ and 5+♠ really worth using up the 1NT bid? Would you be better off with a natural 1NT, or with 1NT as some sort of transfer?

I looked at 100 hands (responder constrained to have 7+) and broke down the responses as...

Pass.....7 hands, guessing 5 or more of them had 4+ hearts
dbl......24 (I'm doubling with 4 hearts on the side, doesn't seem problematic)
1S......24
1N......21
2C.......8
2D.......8
2H.......2
2S.......3
2N.......0
3C.......3 (preempting most 6 cd suits)

100 hands is hardly anything but I think it gives a crude approximation for the lower and most frequent bids. I think it's a pretty nice distribution.

Of the 2D responses (showing 3 diamonds and 4+ clubs)
.....2 4-3 diamond fits at the 2-level
.....2 5-3 diamond fits at the 2-level
.....1 4-4 club fit at the 3-level
.....1 5-3 club fit at the 3-level
.....2 5-4 club fits at the 3-level

I see some advantages to using 1S as clubs. I thought to have it show diamonds because....
.....1) diamonds are higher ranking than clubs and I'd rather miss out on clubs
.....2) it allows 1D (1H) 1S P 2C when opener has something like AQxx xx xx AJxxx. Basically the 2C bid shows clubs but likely has diamond tolerance. Imagine if 1S showed clubs and opener had AQxx xx AJxxx xx. He'd have to bid an uncomfortable 2D.
.....3) it fits with 2C forcing so that 1D (1H) 2C P 2D is natural. If 1D (1S) 2C shows 4+D/3C then 1D (1S) 2D I suppose would show forcing diamonds, but opener couldn't easily show clubs except for 3C. Basically 2C leaves more room for exploration.
.....4) It allows responder to show both minors in an invitational sort of way. 1D (1H) 1S P 1N P 2C ought to be invitational+ (be interested to know if you think it should be forcing) because responder must have something better than a hand that would have shown both minors (2S) directly. The principle also works in competition (responder bids 1S and later competes to 3C).

I think showing the fifth spade is worth the 1N bid. If it didn't, we'd be doubling with 45% of our hands and that feels too high. So often we have at least a 5-2 spade fit. More important, it then allows 1D (1H) dbl P 1S to show something other than three spades. I'm still wrestling with it, but I think it should probably show heart shortness or weakness so as to allow responder to declare 1N when that's right. I.e. it's true that we can eventually figure out whether we have a spade fit or not, but the sooner we know we're not fitting, the sooner we can look elsewhere.

Do you like it better or do you have the same concerns?

[straube]

bluecalm, on 2011-February-19, 14:35, said:

I played:
dbl = 4+spades
1♠ transfer to NT or clubs
1NT = natural
2♣ = transfer to diamonds
2♦ = transfer to opponents suit, general gf/stopper ask
2♥ = transfer to 6+spades weak or GF
2♠ = clubs , weak or GF
2NT = natural
3♣/3♦ natural, invitational
3♥ 6+spades, invitational
3♠ tranfer to 3NT
3NT = to play

when playing precision;

We used the same structure over 1D - 1S (the club suit is sometimes lost there but there are other advantages)

I think I like the 2-way 2H bid better than my use for only weak.

[awm]

straube, on 2011-February-19, 16:20, said:

I see some advantages to using 1S as clubs. I thought to have it show diamonds because....
.....1) diamonds are higher ranking than clubs and I'd rather miss out on clubs

On these hands, your opponents have already shown hearts and you've also determined that you won't have a major suit fit (opener has no 5M, responder has no 4M). With this given, the opponents will be competing in a major if they are competing. I don't see that it matters which minor is higher ranking.

straube, on 2011-February-19, 16:20, said:

.....2) it allows 1D (1H) 1S P 2C when opener has something like AQxx xx xx AJxxx. Basically the 2C bid shows clubs but likely has diamond tolerance. Imagine if 1S showed clubs and opener had AQxx xx AJxxx xx. He'd have to bid an uncomfortable 2D.

First, you're unlikely to have those types of hands without a heart raise or double of 1♠. What does advancer have anyway? Second, if you do have those hands and advancer isn't bidding, an awful lot of the time 1NT will be your spot.

straube, on 2011-February-19, 16:20, said:

.....3) it fits with 2C forcing so that 1D (1H) 2C P 2D is natural. If 1D (1S) 2C shows 4+D/3C then 1D (1S) 2D I suppose would show forcing diamonds, but opener couldn't easily show clubs except for 3C. Basically 2C leaves more room for exploration.

My suggestion is more like: 1♠ = clubs and any strength, but if minimum not interested in diamonds; 2♣ = some interest in both minors, less than invitational; 2♦ = basically to play with 5+♦. Then 2♠ can be used to show a strong diamond bid (primarily stopper ask). This lets you get out in 2m on a wide range of hands where the fit is not so good.

straube, on 2011-February-19, 16:20, said:

.....4) It allows responder to show both minors in an invitational sort of way. 1D (1H) 1S P 1N P 2C ought to be invitational+ (be interested to know if you think it should be forcing) because responder must have something better than a hand that would have shown both minors (2S) directly. The principle also works in competition (responder bids 1S and later competes to 3C).

Sure, but you can bid 1♠...2♦ for the same hand where 1♠ = clubs. I guess you're forced to 2NT or 3m a bit more often, but I'd much rather be forced to 2NT/3m on my invites than by forced to 3♣ on competitive hands with only an eight card club fit (like your 2♦ bid seems to accomplish).

straube, on 2011-February-19, 16:20, said:

I think showing the fifth spade is worth the 1N bid. If it didn't, we'd be doubling with 45% of our hands and that feels too high. So often we have at least a 5-2 spade fit. More important, it then allows 1D (1H) dbl P 1S to show something other than three spades. I'm still wrestling with it, but I think it should probably show heart shortness or weakness so as to allow responder to declare 1N when that's right. I.e. it's true that we can eventually figure out whether we have a spade fit or not, but the sooner we know we're not fitting, the sooner we can look elsewhere.

What does opener have if he has heart shortness but not a spade fit? And how often is advancer passing here anyway? I just don't think this is a critical concern. The issue shouldn't be "how often are we doubling" but rather, "how are our results when we are doubling?" If double showing 4+♠ is getting you bad results (and you would get better results if you distinguished spade length further) then showing 5+ spades is fine, but I've had very little trouble with this particular method and also feel like I can buy the contract in a good 1NT more often by having a natural 1NT bid. What is your call with 2335 hands anyway? A natural 1NT is unavailable, a 2♣ bid is unfortunately forcing, and a 2♦ bid seems likely to get you to a 4-3 diamond fit (even sometimes when you have a 5-3 club fit).

[bluecalm]

Quote

I think I like the 2-way 2H bid better than my use for only weak.

General idea (after both 1H and 1S overcalls) is:
1NT/2NT/3NT is always natural
1S is transfer to NT or clubs (opener treats it as transfer to 1NT)
Jumps to 3level below overcalled suit is natural invitational.
All other bids are transfers which are weak or strong.
1D - 1S - dbl is 4+hearts any strength or 5hearts 7-11 (so 2D is either 6hearts or 5hearts (almost) GF)

I played this after both precision 1D and polish 1C. The idea is from Martens.
I think advantage is simplicity because rules above apply to all the bids and are easy to remember.

[straube]

What is your thought then for a complete structure? Something like...

dbl-4+ spades
1S-clubs
1N-natural
2C-some minor interest, perhaps more in diamonds than clubs
2D-to play
2H-6S weak or strong?
2S-5/4 minors
2N-inv
etc?

Perhaps you were thinking only of 2C as some minor interest in the context of 1N showing 5 spades.

I've thought of other reasons for separating 4 from 5 spades. If dbl shows 4 and 1N shows 5

1D (1H) 1N* (2H) dbl can be support (showing 2) or it can be used as a good or bad raise (a bad raise including xx) of spades.

1D (1H) 1N* (3H) dbl can show 3 spades and 3S can show 4 spades (or good vs bad raise)

1D (1H) dbl (2H) dbl probably still shows 3 spades, but one could explore good vs bad raises or showing minors, etc.

I've thought that if we were to use 2D to show 3 diamonds and 4 or 5 clubs that we probably should restrict it to 9-11 hcps. Opener could then take a shot at 2N with a balanced 4-4-3-2 (the death hand) or many other poorly fitting patterns.

Still mulling over the other points you made.

[awm]

Pretty much what you stated, except that you need a way to show a good hand with diamonds. My suggestion was to use 2♠ for this, and hands with both minors would bid 2♣.

[straube]

I tallied both structures as I understand them for 100 hands. The thing I wasn't careful about was using the 2H (showing 6 spades weak or strong) but regardless...

With 1N natural........With 1N as 5 spades

P.......3.......................3 (These were 7+ hcp hands. I didn't look at 0-6)
dbl...57.....................23
1S....15.....................25
1N....12....................33
2C.....1......................3
2D.....4......................6
2H.....0......................0 Again, I didn't look for these
2S.....2......................3
2N.....2......................2
3m....3......................3
3N.....1......................1

The tallies for spade hands were awfully high and that's probably an aberration due to the small sample size.

Of my 2D bids (restricted to 9-11 hcps)
.....2.....4/3 diamond fits (both times a 5/3 club fit had been available)
.....3.....5/3 diamond fits
.....1.....2N with 21 hcps

I used your 2C bid to handle minors with a diamond preference and I use 1D (1H) 1S P 1N P 2C to show minors with a club preference. That may not be what you intended. Between that treatment and the availability of a more attractive natural 1N, the 2C bid was underrepresented.

Personally, I think that 1D (1H) 2H should show 6 spades and GI+, not the weak or strong variant. GI+ lets opener do something other than accept the transfer. This also means that 1D (1H) 1N P 2C P 2S could be toughing it out with a goodish 5-cd suit.

Do you have agreements about re-opening after 1D (1H) P P ?

Thinking...

dbl-takeout with 3 spades (probably 3-2-4-4 or 3-2-(53))
1S-takeout with 4 spades
1N-minors
2C-4S/5C
2D-4S/5D

If anyone has ideas for opener's rebid after 1D (1H) dbl showing only 4 spades, I'd appreciate them.

[straube]

1D (1H)

dbl-four+ diamonds or three diamonds GI+
.....1S-clubs
.....1N-balanced
.....2C-good raise?
.....2D-bad raise?
1S-four (only) spades
.....1N-all else
.....2C-minors
.....2D-diamonds
.....2H-good raise
.....2S-weak raise
1N-five+ spades
.....2C-4+ clubs
.....2D-5+ diamonds
.....2H-good raise
.....2S-weak raise, possible xx
2C-four+ clubs, f
.....2D-four diamonds
2D-9-11, 3 diamonds, 4-5 clubs
2H-6 spades, GI+
2S-5/4 minors, competitive

[akhare]

straube, on 2011-February-21, 01:23, said:

1D (1H)

dbl-four+ diamonds or three diamonds GI+
.....1S-clubs
.....1N-balanced
.....2C-good raise?
.....2D-bad raise?

IMO, this structure seems much worse than what had been suggested before.

The statistics (80% chance of atleast a 8 card fit in the minors, but only a 32% chance of a 9+ minor card fit) point to what Adam suggested, i.e., but with some tweaks.

Basically, 2♠ as 5-4 in the minors might get us too high.

Also, responder has exactly 4♠ about 26% of the time and 5♠ about 16% of the time. Note that the inability to distinguish between 4/5 ♠ costs only when they can blast to 3♥. IMO, this doesn't warrant giving up a natural 1N given that responder ranks to have 4♥ 15% of the time and 3-4♥ 45% of the time (stoppers is a different issue).

In the interest of symmetry with the 1♦ - (1♠) structure:

Pass <All else>
dbl-4+ spades
1S-Clubs, at least NFB
1N-natural
2C-Diamonds, at least NFB
2D-5♠, minor side suit, at least competitive
2H-6S weak or strong
2S- 4♠, 5+ m, competitive
2N-inv
3m: 4♠, 5+m, GF

[straube]

I think it's better.

I've been trying to figure out what the best 1S rebid is after 1D (1H) dbl showing four spades and have realized that while we could find a use for it, it's not all that necessary.

Think about one bid that promises exactly four spades (and denies a longer minor unless less than GI)and another bid that promises 4+ diamonds and can be anything upward of 7 hcps. Which is more poorly defined? I'd say the diamond hand. We ought to leave more room for the poorly defined hands.

Think, too, about where we are in the auction after 1D (1H) compared to natural 1m (1H) tables. Others have a simple raise as well as a natural 1N bid to show 7-10 strength. They also have the ability to distinguish between four and five spades. I want that, too.

When you try to keep a natural 1N, you have difficulty because you then have to have separate bids to handle the exact same patterns that would bid 1N when responder doesn't have a stopper. If you have xxx Ax Kxxxx Qxx, you don't have a problem. What's your plan for something like Axx xx Kxxxx Qxx? Are you going to transfer to diamonds opposite potentially a void? If you pass such a hand, your problem won't get easier after a 2H advance. Granted, the reverse problem for me is Axx xx Qxx Kxxxx in which case I'm forced to bid 2D. But the bid isn't unilateral. It's rather well-defined and allows for 2N and 3C...even possibly 2S. After a 2H advance, opener can choose whether to compete.

I've thought about 1D (1H) 2C to show 3D/4+C. It allows for 2C contracts which is big. It also means then that we have to use 2D to show clubs (forcing) and that really cramps the constructive auctions. Opener can't show diamonds, spades, and cue at the 2-level. I'd rather play in some 4-3 diamond fits at the 2-level than hamstring our constructive auctions.

I think the 1D (2H) 2S showing minors is a huge winner. It's very unlikely that we don't have an 8-cd or better fit and having 2N as an ask (for better minor) is the key to finding it. Sure, I'd like to play a comfortable 2m, but aren't the opponents very likely to find 2M? I'm quite happy to find an 8-cd minor fit against this. Let the opponents decide whether to compete to 3M and which major to choose. Let them sort out their strength, too.

The statistics you ran for 4 vs 5 cd spade suits were surprisingly low. Were you not counting the 6 cd spade suits? 4 vs 5+ should be closer to parity but granted that some of the 5+ are moved into the 2H bid. I'm pretty sure now that the 2H bid should be GI+ with 6 spades. It allows opener the ability to do something other than accept the transfer. For instance, if you have the GF hand, you prefer to hear 1D (1H) 2H P 3S when you're deciding about whether to slam.

I think 1D (1H) dbl (3H)auctions happen often enough that we have to concern ourselves with them. Not only that, but 1D (1H) dbl (2H) auctions are very common. I'm very willing to play in a 5-2 spade fit against that, but we have no way of finding that fit unless we know partner has five spades. We have to remember that most other pairs in the room are able to show 5 vs 4. On top of that, we don't have a backup plan. After they compete to 2H, responder might have something like a 5-2-2-4 and they might or might not have a club fit on the side. Other pairs might have started 1C (1H) 1S showing 5 (2H) P P and now that opener hasn't make a support double, they might guess to balanced with 3C. We can't do that so we need to think more about that 5-2 option.

[akhare]

straube, on 2011-February-21, 11:58, said:

I think it's better.

The statistics you ran for 4 vs 5 cd spade suits were surprisingly low. Were you not counting the 6 cd spade suits? 4 vs 5+ should be closer to parity but granted that some of the 5+ are moved into the 2H bid. I'm pretty sure now that the 2H bid should be GI+ with 6 spades. It allows opener the ability to do something other than accept the transfer. For instance, if you have the GF hand, you prefer to hear 1D (1H) 2H P 3S when you're deciding about whether to slam.

...

I think the 1D (2H) 2S showing minors is a huge winner. It's very unlikely that we don't have an 8-cd or better fit and having 2N as an ask (for better minor) is the key to finding it

OK, instead of guessing, why not start off by looking at the probabilities of fits after a 1♦ opening and 1♥ overall.

1) The hands with 6+♠(6%) pretty much take care of themselves and we don't have to worry about combining them with the 4/5 ♠ hands.

2) Regarding your assertion about 2♠ being a huge winner, it may be true if you are willing to promise atleast 4-4 in the minors because 5-4 hands in the minors are exceedingly rare.

Responder has 5-4 in minors: 0.08937
We have 8 card Clubs Fit: 0.36605
We have 8 card Diamonds Fit: 0.39567
We have 9 card Clubs Fit: 0.14739
We have 9 card Diamonds Fit: 0.16685
We have Spades Fit: 0.3018
Frequency Responder spades distribution:
0 518
1 4426
2 15502
3 27465
4 27692
5 16576
6 6203

Perhaps someone can check my dealer script for errors:

# This example creates hands to illustrate the 1D opening
# South is assumed to be the dealer in all cases

#Balanced 11 - 13 hands
BalancedHands = hcp(south) >= 11 && hcp(south) <= 13 && shape(south, any 4432 + any 4333 + any 5332 - 5xxx - x5xx)

#Three suited hands
ThreeSuited = hcp(south) >= 10 && hcp(south) <= 15 && shape(south, any 4441 + any 5431 + any 5440 - 5xxx - x5xx)

#Diamonds and major
DiamondMajor = hcp(south) >= 10 && hcp(south) <= 15 && shape(south, 4x6x + x46x + 4x7x + x47x)

#Club fit
ClubsFit = clubs(south) + clubs(north) >= 8
DiamondsFit = diamonds(south) + diamonds(north) >= 8
BigClubsFit = clubs(south) + clubs(north) >= 9
BigDiamondsFit = diamonds(south) + diamonds(north) >= 9

#Used to calculate 5-4 in the minors in responder's hand
MinorsHand = (diamonds(north) >= 4 && clubs(north) >= 5) || (diamonds(north) >= 5 && clubs(north) >= 4)
HeartsFit = hearts(south) + hearts(north) >= 8
SpadesFit = spades(south) + spades(north) >= 8

#Use to simulate heart overcall assuming 5+ hearts and 8+ HCP
HeartO = hearts(west) >= 5 && hcp(west) >= 8 && hcp(west) < 15
SpadeO = spades(west) >= 5 && hcp(west) >= 8 && hcp(west) < 15

condition
(BalancedHands || ThreeSuited || DiamondMajor) && HeartO

produce
100000

action
frequency "HCP" (hcp(south), 10, 15),
average "Responder has 5-4 in minors" MinorsHand,
average "We have 8 card Clubs Fit" ClubsFit,
average "We have 8 card Diamonds Fit" DiamondsFit,
average "We have 9 card Clubs Fit" BigClubsFit,
average "We have 9 card Diamonds Fit" BigDiamondsFit,
average "We have Spades Fit" SpadesFit,
frequency "Responder spades distribution" (spades(north), 0, 6),

[straube]

akhare, on 2011-February-21, 13:15, said:

OK, instead of guessing, why not start off by looking at the probabilities of fits after a 1♦ opening and 1♥ overall.

1) The hands with 6+♠(6%) pretty much take care of themselves and we don't have to worry about combining them with the 4/5 ♠ hands.

2) Regarding your assertion about 2♠ being a huge winner, it may be true if you are willing to promise atleast 4-4 in the minors because 5-4 hands in the minors are exceedingly rare.

Responder has 5-4 in minors: 0.08937
We have 8 card Clubs Fit: 0.36605
We have 8 card Diamonds Fit: 0.39567
We have 9 card Clubs Fit: 0.14739
We have 9 card Diamonds Fit: 0.16685
We have Spades Fit: 0.3018
Frequency Responder spades distribution:
0 518
1 4426
2 15502
3 27465
4 27692
5 16576
6 6203

Perhaps someone can check my dealer script for errors:

# This example creates hands to illustrate the 1D opening
# South is assumed to be the dealer in all cases

#Balanced 11 - 13 hands
BalancedHands = hcp(south) >= 11 && hcp(south) <= 13 && shape(south, any 4432 + any 4333 + any 5332 - 5xxx - x5xx)

#Three suited hands
ThreeSuited = hcp(south) >= 10 && hcp(south) <= 15 && shape(south, any 4441 + any 5431 + any 5440 - 5xxx - x5xx)

#Diamonds and major
DiamondMajor = hcp(south) >= 10 && hcp(south) <= 15 && shape(south, 4x6x + x46x + 4x7x + x47x)

#Club fit
ClubsFit = clubs(south) + clubs(north) >= 8
DiamondsFit = diamonds(south) + diamonds(north) >= 8
BigClubsFit = clubs(south) + clubs(north) >= 9
BigDiamondsFit = diamonds(south) + diamonds(north) >= 9

#Used to calculate 5-4 in the minors in responder's hand
MinorsHand = (diamonds(north) >= 4 && clubs(north) >= 5) || (diamonds(north) >= 5 && clubs(north) >= 4)
HeartsFit = hearts(south) + hearts(north) >= 8
SpadesFit = spades(south) + spades(north) >= 8

#Use to simulate heart overcall assuming 5+ hearts and 8+ HCP
HeartO = hearts(west) >= 5 && hcp(west) >= 8 && hcp(west) < 15
SpadeO = spades(west) >= 5 && hcp(west) >= 8 && hcp(west) < 15

condition
(BalancedHands || ThreeSuited || DiamondMajor) && HeartO

produce
100000

action
frequency "HCP" (hcp(south), 10, 15),
average "Responder has 5-4 in minors" MinorsHand,
average "We have 8 card Clubs Fit" ClubsFit,
average "We have 8 card Diamonds Fit" DiamondsFit,
average "We have 9 card Clubs Fit" BigClubsFit,
average "We have 9 card Diamonds Fit" BigDiamondsFit,
average "We have Spades Fit" SpadesFit,
frequency "Responder spades distribution" (spades(north), 0, 6),

[straube]

Yes, the 2S bid promises 5/4 either way. The only exception I would consider is when responder holds four of their major (rare). This exception means that the opponents have at least an 8-cd fit in the other major. If you run your statistics on that, I would expect that our ability to find an 8-cd fit (by bidding 2S with 1-4-4-4 for example after an 1H overcall) is 90+ %.

[akhare]

straube, on 2011-February-21, 14:00, said:

Yes, the 2S bid promises 5/4 either way. The only exception I would consider is when responder holds four of their major (rare). This exception means that the opponents have at least an 8-cd fit in the other major. If you run your statistics on that, I would expect that our ability to find an 8-cd fit (by bidding 2S with 1-4-4-4 for example after an 1H overcall) is 90+ %.

The 90% number is way too high -- it's more like 75%. I think you are forgetting that opener may have hearts length as well and the opps won't always have a 8 card fit.

Responder has 5-4 in minors: 0.09098
Responder has club preempt: 0.03224
Responder has diamond preempt: 0.02967
Responder has club GF: 0.04557
Responder has club GF and 4H: 0.00301
Responder has diamond GF: 0.0427
Responder has diamond GF and 4H: 0.0025
Responder has five spades and a minor: 0.08283
Responder has four spades and a minor: 0.08283
Responder has five spades and balanced hand: 0.04274

Anyway, regarding the 4/5 ♠ differential, it seems in your proposed responses, the 1N bid specifically targets the the 5♠ in balanced hand. It may not be true from the purely design POV, but that's the only information the bid has conveyed.

Basically, how well placed opener is to compete after an auction that goes 1D - (1♥) - 1N (showing 5♠) - (2♥). Opener can compete in ♠ with say 2♠, but we may have a much better fit in either minor.

In the case of the of 1D - (1♥) - 1♠ (showing 4♠) - (2♥), opener is even worse placed than before.

As you can see from the statistics, the 5♠ - side suit minor hands twice as frequent as the balanced hands with 5♠, and bids that immediately convey that information and least clue in opener about the possibility.

The same is true for bids that convey 4♠ - 5 card minor.

[Edit]
With that in mind I think it's possible to meld the elements from both approches:

Pass <All else>
dbl-4/5♠, including GF hands
1S- Transfer to NT, could be NFB+ in ♣ or GF in ♦
1N-4/5♠, 4+ cards in a minor, competitive
2C-4+♣, 5♠, competitive
2D-4+♦, 5♠, competitive
2H- 6♠, weak or strong
2S: Minors, competitive
2N-inv
3C: GF with ♣

This post has been edited by akhare: 2011-February-21, 18:20

[straube]

Quote

The 90% number is way too high -- it's more like 75%. I think you are forgetting that opener may have hearts length as well and the opps won't always have a 8 card fit.

I wrote that the opponents always have an 8+ fit in their other major (in this instance spades) when responder has a 4441 including the overcalled major.

I tallied the results from 50 hands and found that by bidding 2S with a 1-4-4-4 after a 1H overcall that we would find minor suit fits thusly...

8% 7-card fit
44% 8-card fit
48% 9-card fit

No 10-cd fits because I didn't include the possibility of opener having 6D/4M. In reality, since the balanced 10, 14, and 15 pt hands should be removed from the sample (meaning more with minor suit configurations), I would expect that the likelihood of finding an 8+ fit to be even higher than 92%. Perhaps you can run a simulation.