[straube]

Looking for help with 2H interference of our nebulous 1D (10-15, no 5M, no 6m unless 5m/6m). Is this good? Can we do better?

1D (2H)

dbl-negative or NFB spades
.....2S-2 to 4 spades
..........P-NFB
..........2N-GI 4 spades
..........cue-GF stopper ask
..........other-natural, GI 4 spades
.....3S-4 spades, max
2S-GI+, spades
2N-asks better minor (competitive both minors or GI+ diamonds)
.....3C-clubs
..........3D-to play
.....3D-diamonds, weak
.....other-natural and diamonds, max
3C-GI
3D-GF clubs
3H-stopper ask
3S-weak

[rbforster]

What do you do with a balanced invite, say a hand that wants a natural 2N call? Seems like that one gets lost trying to cater to the weak long spades hands. Given they're already showing weakness and your opener is limited, it seems like you might not want to prioritize weak hands by responder.

[straube]

Thanks for your feedback. I'll try to defend it but I'd be interested to know if you agree with my reasoning or if you think the invitational 2N is just too important.

We used to play 2S as a negative free bid and we used to play Transfer Lebensohl with similar reasoning that others play 1N (2S) 2N as some form of Lebensohl. Very often
opener has an 11-13 balanced hand and the idea is to assume that and decide (with that balanced invite) whether to go high or low. 2N is kind of an inglorious contract
and compared to other folks who open a natural minor and face 2H, we might be in 2N when those folks are in 3m.

After 1D (2H) 2N we would really have little use for the 3-level. Unless opener has 5/5 in the majors that is. I suppose opener could rebid 3D to play with 4153 or something but we've no guarantee of a diamond fit. So other than 3N, a natural 2N is kind of a dead end.

The other thing is this would get us invitational as well as forcing ways of bidding minors as well as being able to competitively handle all 5/5 hands. With 5S/5m dbl and play 2S if offered or correct to diamonds if opener is short spades. Might even handle 5S/4m as opener will have at least 3-cd support for that minor and usually 4-cd support.

Probably the last thing is just a frequency issue. 2N invitational with no 4 spades and no 6-cd minor and heart stopper but not wanting to trap....

If you think we need 2N invitational, any suggestions for the rest of the structure?

[rbforster]

Can you clarify what your 1D opener is? I guess it's often 11-13 balanced, but then can be many unbalanced hands without 5M or 6m.

[straube]

Sure. 11-13 bal, 5+m/5+m, 5m431,5m440, 4441. We open 6m/4 with 2m

I feel like too much is invested in spades. If double handled spades (or maybe dbl and 3H for 6S) and 2S denied spades we might rightside more contracts.

[Kungsgeten]

What would happen if we make the NFB a tad stronger? I'm thinking that the NFB shows constuctive to invitational values.

1D--(2H)--dbl--(pass);
2S = Would have passed the NFB
2NT = 3 spades, extras + heart stopper
3m = Short spades?
3H = 3 spades, extras, no heart stopper

Now I think we could manage if 2NT is GF with 5+ spades, thus leaving 2S and 3m. Perhaps the extra bidding space of 2S can be of some use?

[straube]

Yeah, probably stronger.

I looked at hands and slightly less than half of responder's hands had 4 or more spades which makes me wonder if assigning both dbl and 2S to spade hands makes sense. Maybe it does though.

[foobar]

Here's some data from a dealer script (scroll to the end) that might help you. The total number of hands produced were ~96,000, and since it's pretty close to 1,00,000, you can add the frequency data to get an approximate % of relative frequencies.

For example, the 1D opener (south) will hold frequently hold 3-4 ♠, but responder holds exactly 5♠ < 20% of the time.

South spades: 3.16151
North spades: 3.78056
Frequency south spades:
0 249
1 3644
2 16655
3 35228
4 40189
Frequency north spades:
0 310
1 3062
2 12484
3 24922
4 27643
5 18195
6 7283
7 1802
8 231
High 33
South clubs: 3.68685
North clubs: 3.52671
Frequency south clubs:
0 78
1 1810
2 10746
3 26452
4 33244
5 23635
Frequency north clubs:
0 569
1 4764
2 15748
3 27060
4 26119
5 15126
6 5319
7 1110
8 139
High 11
South diamonds: 3.68518
North diamonds: 3.53636
Frequency South diamonds:
0 98
1 1864
2 10673
3 26521
4 33170
5 23639
Frequency north diamonds:
0 594
1 4750
2 15678
3 26725
4 26215
5 15250
6 5471
7 1114
8 160
High 8
Generated 10000000 hands
Produced 95965 hands
Initial random seed 1455572041
Time needed 14.00 sec

Dealer script follows:

#Some convenient definitions for our openings
#This doesn't need changing

LimitedOpening = hcp(south) >=10 && hcp(south) <= 15
NoFiveCardMajor=spades(south) < 5 && hearts(south) < 5
BalancedHand=shape(south, any 4432+any 5332+ any 4333)
WeakNTNoMajor=hcp(south) >= 11 && hcp(south) <= 13 && BalancedHand && NoFiveCardMajor
1DUnbalanced=LimitedOpening && !BalancedHand && NoFiveCardMajor && diamonds(south) < 6 && clubs(south) < 6

#Actual definitions for our openings
#This doesn't need changing

TwoDiamondOpening=LimitedOpening && NoFiveCardMajor && diamonds(south) >= 6
TwoClubOpening=LimitedOpening && NoFiveCardMajor && clubs(south) >= 6 && !TwoDiamondOpening
FirstNTOpening=hcp(south) >= 14 && hcp(south) <= 16 && BalancedHand
ThirdNTOpening=hcp(south) >= 15 && hcp(south) <= 17 && BalancedHand
OneSpadeOpening=LimitedOpening && spades(south) >= 5
OneHeartOpening=LimitedOpening && hearts(south) >= 5
OneDiamondOpening=WeakNTNoMajor || 1DUnbalanced
StrongClub=hcp(south) >= 16 && !FirstNTOpening

#Some definitions to allow biasing of overcalls
#This can be changed by addding additional entries

HeartsWest=hcp(west) >= 8 && hearts(west) >= 5 && spades(west) < 5
SpadesWest=hcp(west) >= 8 && spades(west) >= 5 && hearts(west) <=4
ClubsWest=hcp(west) >= 10 && clubs(west) >= 6
DiamondsWest=hcp(west) >= 10 && diamonds(west) >= 6
HeartsEast=hcp(east) >= 8 && hearts(east) >= 5 && spades(east) < 5
SpadesEast=hcp(east) >= 8 && spades(east) >= 5 && hearts(east) <=4
ClubsEast=hcp(east) >= 10 && clubs(east) >= 6
DiamondsEast=hcp(east) >= 10 && diamonds(east) >= 6

WeakHeartsWest=hcp(west) >= 6 && hcp(west) <= 10 && hearts(west) >= 6 && spades(west) < 5

#Change condition to control the hands that are generated
#Examples:
#Strong club hands: condition StrongClub
#Strong club hands with LHO interference: condition StrongClub && (SpadesWest || HeartsWest || ClubsWest || DiamondsWest)
#Strong club hands with LHO OR RHO interference: condition StrongClub && ((SpadesWest || HeartsWest || ClubsWest || DiamondsWest) || (SpadesEast || HeartsEast || DiamondsEast || ClubsEast))

condition OneDiamondOpening && WeakHeartsWest && hcp(north) >= 8 && spades(south) < 5 && hearts(south) < 5 && clubs(south) < 6 && diamonds(south) < 6
produce 100000
dealer south
action
average "South spades" spades(south), average "North spades" spades(north),
frequency "south spades" (spades(south), 0, 4), frequency "north spades" (spades(north), 0, 8),
average "South clubs" clubs(south), average "North clubs" clubs(north),
frequency "south clubs" (clubs(south), 0, 5), frequency "north clubs" (clubs(north), 0, 8),
average "South diamonds" diamonds(south), average "North diamonds" diamonds(north),
frequency "South diamonds" (diamonds(south), 0, 5), frequency "north diamonds" (diamonds(north), 0, 8)

[straube]

1D (2H)

dbl-5 spades GI OR 4 spades OR like a natural 2N invitational
.....2S-minimum, 4 spades or 3 spades if no stopper
..........P-minimum, 4+ spades
..........2N-invitational, not 4 spades
..........3m-4S/5m
..........3H-asks stop
.....2N-minimum, stopper
.....3C-minimum, could be 5D/4C
.....3D-minimum, strong diamond preference
.....3H-asks for stopper
.....3S-maximum, fit
.....3N-maximum, stopper

2S-5 spades, forcing
2N-competitive minors or GI+ diamonds
3C-GI
3D-GF clubs
3H-6 spades, GI+
3S-stopper ask?
3N-to play

Occasionally this leads to playing 4-3 spade fits when 2N might be better. You'd also have to know how to handle an advance of 3H.

[awm]

After 1d-(2h)-X it seems like the 2s rebid should show four. Some reasons:

1. Responder is significantly more likely to have four spades than five (as per foobar's stats, plus the four spade hands include GF ones).
2. What is responder to do with 4S and inv values after the 2s rebid? 2nt misses a possible fit, 3s commits to a 3-level moysian much of the time, and other actions effectively force game.

[straube]

awm, on 2016-February-18, 13:29, said:

After 1d-(2h)-X it seems like the 2s rebid should show four. Some reasons:

1. Responder is significantly more likely to have four spades than five (as per foobar's stats, plus the four spade hands include GF ones).
2. What is responder to do with 4S and inv values after the 2s rebid? 2nt misses a possible fit, 3s commits to a 3-level moysian much of the time, and other actions effectively force game.

I'd considered that, along with dbl showing 5 spades....but dbl showing 5 spades seems wrong, too, on a frequency basis. If 2S promised 4 GI, do you have anything in mind for the rest of the structure? Maybe dbl should be invitational other....or even GF other.

[foobar]

straube, on 2016-February-18, 13:46, said:

I'd considered that, along with dbl showing 5 spades....but dbl showing 5 spades seems wrong, too, on a frequency basis. If 2S promised 4 GI, do you have anything in mind for the rest of the structure? Maybe dbl should be invitational other....or even GF other.

Based on the data, there are couple of reasonable approaches:

X: 4+ spades
.....2S: 4♠
2♠: 5+ ♠
2N: Natural, invite (stopper may be nebulous in a pinch, and opener may express doubt by bidding 3♥)
3m: Natural, forcing


X: 4+ spades
.....2S: 4♠
2♠: Ostensibly minors, maybe a signoff in diamonds?
.....2N: Denies 4cm
.....3m: Preference
2N: Natural, invite
3m: Natural, forcing

[straube]

I'd totally misread Adam's post. I had been thinking about 1D (2H) 2S forcing with four spades and dbl promising 5 spades.