[nullve]

Thought I should post my notes on the defense against 2-level suit preempts that nullve-nullve play against nullve-nullve.

----------

I've long been convinced that the standard overcall scheme, where

(2x)-?:

(...)
X = takeout, but 18(19?)+ if BAL w/o tolerance for all unbid suits
2N = 15-17 (or, God forbid, 15-18) BAL
(...),

should be replaced with

(2x)-?:

(...)
X = takeout, except that the range on BAL w/o tolerance for all unbid suits is 15-17/21+ (=> 2N+: see below)
2N = "18-20 BAL" / see below
(...),

for several reasons, e.g.:

• There will be more ways to avoid no-play 2N contracts when Advancer has very little opposite 15-17 BAL;
  
• It will be possible to stop below game when Advancer has very little opposite 18-20 BAL;
  
• Doubling with 15-17/21+ instead 18+ BAL if BAL puts more pressure on opps, especially if 2x doesn't promise 6+ x so that Responer might attempt to improve the contract;
  
• The 2N overcall (made with 18-20 instead of 15-17(18) if BAL) is more amenable to including a weaker option (such as a "bad" standard 3♣ overcall), which in turn could make it easier to play a very different type of overcall scheme. (See below.)

The main price to pay is that advances to the double have to be different and likely include a 2N advance that allows Overcaller to pass with with 15-17 BAL. And that would mean a loss of precious bidding space although I believe it's still possible to have a decent structure.

Anyway, here is, holes included, what nullve-nullve have been playing for many years, when x=♠:

(2♠)-X-?:

P = normal (i.e. LoTT-based, as usual), but see below
2N = NF lebensohl, 4- H
...P = "15-17 BAL" w/o tolerance for all unbid suits
...3♣+ = as opposite normal lebensohl
3♣ = 0-7, 5+ H / INV+, 4+ D / GF, 3- H
...3♦ = would have passed a 3♦ advance playing standard lebensohl
...3♥ = P/C, GF opposite the D hand
......P = 0-7, 5+ H
......3♠+ = NAT GF
...3♠+ = NAT GF
3♦ = INV+, 5+ H
...3♥ = would have passed a 3♥ advance playing standard lebensohl
...3♠+ = NAT GF
3♥ = INV, 4 H
3♠ = GF values, 4 H, either no S stopper or very strong
3N = GF values, 4 H, S stopper. NF
(...).

As in Transfer lebensohl and GUCI lebensohl, there is no way to show INV with lcubs and the following hand types become particularily problematic (and maybe more problematic than in Transfer lebensohl/GUCI lebensohl):

1) 9-10, 4S4C(32)
2) 9-10, 3334
3) 9-10, 2335
4) 9-10, 3(32)5
5) 8-10, 1-suited w/ 6+ C

(list probably not exhaustive)

It's obviously possible to play something very similar to this over (2♥)-X, e.g. with 3♦ = 8+, 5+ S and 3♠ = INV, 4 S, but because Overcaller will bid again over (2♥)-X-2♠ with 15-17 BAL, it might be better to do away with mild spade invites by Advancer and play

(2♥)-X-?:

P = normal (i.e. LoTT-based, as usual), but see below
2♠ = < strongly INV, 4+ S (or, maybe, 3334/3(32)5 --- see below)
...P = MIN
...2N = "15-17 BAL", 2-3 S (=> 3m = to play)
...3♠ = mildly INV (also with 15-17 BAL), 4+ S
...3♣+ = normal, or maybe
...3♣ = extras, 3S5(+)C
...3♦ = extras, 3S5(+)D
...(...)
2N = NF lebensohl, 4- S
...P = "15-17 BAL" w/o tolerance for both minors
...3♣+ = as opposite normal lebensohl
3♣ = INV+, 4+ D / GF, 3- S
...3♦ = would have passed a 3♦ advance playing standard lebensohl
...3♥+ = NAT GF
3♦ = GF (or strongly INV+?), 5+ S
3♥ = GF values, 4 S, either no S stopper or very strong
3♠ = ? (strongly INV w/ 4 S is an option)
3N = GF values, 4 S, H stopper. NF
(...).

Again, there is no way to invite with clubs, so the following hand types are particularly problematic:

6) 9-10, 4H4C(32)
7) 9-10, 3334
8) 9-10, 3235
9) 9-10, 2335
10) 8-10, 1-suited w/ 6+ C
11) 9-10, 3325

(list probably not exhaustive)

My "solutions" to the above problems are based on the fact that Responder didn't raise, so opps have most likely 8- trumps.

1),6) Pass. Not so attractive from a LoTT perspective with 4 small trumps, but...
2),7) Pass(!!). The 4C333 shape is a negative adjustment factor (~ 1 total trick?), so from a LoTT perspective defending against 2MX is easily the best we can do if partner has 2+ M, as suggested by Responder's failure to raise M. Alternatively, if M=♥, 2♠, hoping for a 4-3 fit.
3),8) 3♣. Partner seems to have 3+ S and therefore 15-17 BAL or better.
4),9) Maybe nderbid 2N with 9 (expecting game to be somewhat marginal opposite 15-16 BAL) and overbid 3♣ with 10, hoping partner has a little extra.
5),10) 3♣, hoping the club suit will be a sufficient source of tricks in 3N.
11) 2♠, hoping for a 4-3 S fit.

Of course, these "solutions" will sometimes lead to silly results.

When x=m I think Kokish-Kraft advances are the way to go. (Thx for the tip, dokoko!) I.e. something like

(2♣)-X-?:

P = allowed
2♦ = Herbert
2M = "constructive, 4+ M"
2N = puppet to 3♣
...3♣ = forced
......3♦ = INV+, 4+S4+H
......3M = "GF, 4+ M, C stopper"
......(...)
3y-1(y>♣) = "INV+, 4+ y"
3♠: undefined
3N = suggestion w/ C stopper
(...)

and, similarly,

(2♦)-X-?

P = allowed
2M = "< INV, 4+ M"
2N = "WK w/ C" OR
...3♣ = to play opposite the weak hand
......P = the weak hand
......3♦ = INV+, 4+S4+H
......3M = "GF, 4+ M, D stopper"
...(...)
3♣ = "INV, 4+ C"
3M-1 = "INV+, 4+ M"
3♠: undefined for now (but a kind of transfer to C in the Kokish-Kraft notes)
3N = suggestion w/ D stopper
(...)

So what should the remaining overcall structure look like? I can imagine three different schemes:

I ("natural overcalls"):

(2x)-?:

X: as above
2N = "18-20 BAL"
3N: starts at 21 hcp if BAL
other: normal

II ("transfer overcalls"):

E.g.

(2M)-?:

(...)
2♠(M=♥) = normal overcall
2N = normal C overcall or "18-20 BAL"
3♣ = unlimited D overcall
3♦(M=♠) = unlimited H overcall
(...)

III ("Concept/Flash" overcalls¹):

Main idea: To be able to separate "good" and "bad" overcalls when a Good/Bad 2N-like bid is not available.

(2♣)-?:

P = normal
X = takeout with the above 15-17 BAL/18-20 BAL "inversion"
2♦ = normal² D overcall or bad² H overcall
2♥ = good² H overcall or bad S overcall
2♠ = good S overcall or reds at least 5-5
2N = 18-20 BAL
3♣ = very good² D overcall or majors at least 5-5
3♦ = very good H overcall or pointeds at least 5-5
3♥ = very good S overcall or good overcall with reds at least 5-5
(...).

(2♦)-?:

P = normal
X = takeout with the above 15-17 BAL/18-20 BAL "inversion"
2♥ = normal H overcall or bad S overcall
2♠ = good S overcall or bad overcall with roundeds at least 5-5
2N = bad C overcall or 18-20 BAL
3♣ = good C overcall or majors at least 5-5
3♦ = very good H overcall or blacks at least 5-5
3♥ = very good S overcall or good overcall with roundeds at least 5-5
(...),

Advances to the double have to be a bit different, and the "NT system" after (2♦)-2N-3♣ has to be clever, since Responder can't just transfer to M with 5+M3-OM. One idea:

Spoiler

X = as above or "18-20 BAL", 5 M
...(...)
...2M
......(...)
......3♣ = "18-20", 5 OM
......(...)
2N = as above, but not 5 M if "18-20 BAL"
...3♣
......3♦ = 3+S3+H
.........3♥ = 4+ S
............3♠ = 3S4H
............3N = 3S3H
............4♣+ = 4 S
.........3♠ = 3-S4+H
.........(...)
......3♥ = 2(-)S3+H
.........3♠ = 4+ H
............3N = 3 H
............4♣+ = 4 H
.........(...)
......3♠ = 4S2(-)H
......3N = 3S2(-)H
...(...)
other = as above.

(2♥)-?:

(...)
2♠ = normal S overcall (incl. bad overcall 5+S5+m) or bad overcall with minors at least 5-5
2N = 18-20 BAL or bad C overcall
3♣ = good C overcall or bad D overcall
3♦ = good D overcall or good overcall with blacks at least 5-5
3♥ = strong S overcall or good overcall with minors at least 5-5
3♠ = very strong C overcall or good overcall with pointeds at least 5-5
(...)

(2♠)-?:

(...)
2N = "18-20 BAL" or bad C overcall
3♣ = good C overcall or bad D overcall
3♦ = good D overcall or bad H overcall
3♥ = good H overcall or minors at least 5-5
3♠ = very strong C overcall or reds at least 5-5
(...


More on Concept/Flash overcalls

In order for these overcalls to work when Advancer cannot safely force, he must initially bid as if he can "see" what type Overcaller has, i.e. much like when responding to a "Flash-type" (Major Flash, Red Flash,...) opening bid. With enough to force, he can either show a suit of his own or reality check with either 2N (if available) or a cuebid (if not).

Ex.:

(2♠)-3♣-?

Case: Advancer can "see" that Overcaller has a good C overcall:

P = would have passed a normal 3♣ overcall
3♦/3N+ = same as over a normal 3♣ overcall
3♠ = reality check

Case: Advancer can "see" that Overcaller has a bad D overcall:

P = long C, no D fit, no game interest
3♦ = would have passed D overcall known to be bad
3♥/3N+ = same as over a normal 3♦ overcall, except maybe a bit sounder
3♠ = reality check

Concept/Flash overcalls could also be used against higher preempts, e.g.

Spoiler

(3♣)-?:

(...)
3♦ = normal D overcall or bad H overcall
3♥ = good H overcall or bad S overcall
3♠ = good S overcall or reds at least 5-5
3N = NAT
4♣ = strong D overcall or majors at least 5-5
4♦ = strong H overcall or pointeds at least 5-5
(...)

(3♦)-?:

(...)
3♥ = normal H overcall or bad S overcall
3♠ = good S overcall or roundeds at least 5-5
3N = NAT
4♣ = normal C overcall or majors at least 5-5
4♦ = strong H overall or blacks at least 5-5
(...)

(3♥)-?:

(...)
3♠ = normal S overcall or minors at least 5-5
3N = NAT
4♣ = normal C overcall or pointeds at least 5-5
4♦ = normal D overcall or blacks at least 5-5
(...)

(3♠)-?:

(...)
3N = NAT
4♣ = normal C overcall or reds at least 5-5
4♦ = normal D overcall or roundeds at least 5-5
4♥ = normal H overcall or minors at least 5-5
(...)

Using

(3x)-3N = ART

together with

(3x)-X-3N = lebensohl*, but Overcaller may pass with a standard 3N overcall
(3x)-P-X; 3N = lebensohl*,

is also something I've also been toying with.

* actually played by Marston-Burgess long before I thought of it

The 2N overcall in II and III

Again, Advancer must often bid as if he can "see" which hand type partner has, but now he will systemically transfer to 3M (presumably opposite 18-20 BAL) with 0-5, 5+ M whenever M is an unbid major.

Ex.:

(2M)-2N-?:

P = wants to play 2N opposite 18-20 BAL
3♣ = would have passed the 3♣ overcall, GF opposite 18-20 BAL
...P = the C overcall
...3♦+ = "18-20 BAL"
3OM-1 = 0-5, 5+ OM / ?
(...)

¹ First outlined here, but I took the name from 'similar opening preempts (Concept Preempts, Major Flash and Red Flash) described here, at Chris Ryall's Weak Two Archive.
² By 'bad', 'normal', 'good' and 'very good' ranges I'm currently thinking of something like "11-13", "11-16", "14-16" and "17+", respectively. But (very) good and not-too-unbalanced hands in the "14-16" and "17-19" ranges may be shown as "15-17 BAL" and "18-20 BAL", respectively, if that is more convenient. (It often will be.)

[awm]

If opponents open 2♠ and partner has a 15-17 balanced hand:
1. I can't get out to three of either minor on a weak hand, only 3♥.
2. If we play in 2NT, it will be wrong-sided by my 2NT advance.
3. I have no bid on a set of balanced GF hands with clubs, and we may end up in a silly spot.
4. 4-4 heart fits are wrong-sided.

I see no wins here and plenty of losses. Note that in my normal methods I can get out in 3♦ on a weak hand over a natural 2NT overcall.

If opponents open 2♠ and partner has a takeout double, I don't have a sensible bid on some 9-11 hands with clubs that are easy in standard lebensohl. Otherwise we only seem to break even.

It seems like the only real advantages here are when overcaller has 18-20 balanced, which is a relatively rare hand type.

If opponents open 2♥ there are some potential wins on 15-17 balanced opposite hands with 4♠ (can bid 2♠...3m to get out for example) but we also wrong-side all spade contracts, and there are some corresponding losses when 18-20 balanced faces 4♠.

Overall this seems to add complexity while losing on the more common balanced range (as well as losing a bit on the takeout double).

[nullve]

 awm, on 2020-October-20, 15:20, said:

If opponents open 2♠ and partner has a 15-17 balanced hand:
1. I can't get out to three of either minor on a weak hand, only 3♥.
2. If we play in 2NT, it will be wrong-sided by my 2NT advance.
3. I have no bid on a set of balanced GF hands with clubs, and we may end up in a silly spot.
4. 4-4 heart fits are wrong-sided.

If we are talking about auctions starting (2♠)-X:

1. One exception, of course, is when Overcaller is 2(443) or 2(533) and can rebid 3♣ over 2N (as in standard lebensohl). Another exception is when opps try to escape from 2♠X. (See below.)
2. I'm not so sure about that. While it may be better on average for the defenders to lead a suit through Overcaller than through Advancer, it's probably harder for Opener than for Responder to pick a suit (and a card) that will work the defense.
3. The 3♣ advance is also used on GF hands with 3-H4+C.
4. True.

If we are talking about auctions starting (2♠)-P-(P)-X:

1.,3.,4. Same.
2. True.

 awm, on 2020-October-20, 15:20, said:

I see no wins here and plenty of losses. Note that in my normal methods I can get out in 3♦ on a weak hand over a natural 2NT overcall.

One win is that if Responder has a misfitting hand on which he cannot afford to pass (2♠)-X, which can easily be the case if opps are playing more exotic stuff than a classic weak two, then the 15-17BAL/18-20BAL inversion means we will let them off the hook less often. And it is at least conceivable that a fit can be found after, say,

(2♠)-X-(3♣)-P
(P)-X*,

* takeout of clubs

that cannot be found after

(2♠)-2N*.

* standard overcall

 awm, on 2020-October-20, 15:20, said:

It seems like the only real advantages here are when overcaller has 18-20 balanced, which is a relatively rare hand type.

Yes, relatively rare. But not so rare that those advantages can be ignored.

[awm]

 nullve, on 2020-October-21, 07:50, said:

If we are talking about auctions starting (2♠)-X:

1. One exception, of course, is when Overcaller is 2(443) or 2(533) and can rebid 3♣ over 2N (as in standard lebensohl). Another exception is when opps try to escape from 2♠X. (See below.)
2. I'm not so sure about that. While it may be better on average for the defenders to lead a suit through Overcaller than through Advancer, it's probably harder for Opener than for Responder to pick a suit (and a card) that will work the defense.
3. The 3♣ advance is also used on GF hands with 3-H4+C.
4. True.

1. I don't typically overcall 2NT on these shapes, preferring a takeout double. So I'm not really including these for consideration.
2. Opener is less likely to find a "surprise" lead in another suit, but the lead of overcaller's suit through the strong 2NT bidder is likely to be much more effective than leading into the strong 2NT bidder, especially when opener's suit is not extremely robust (often the case these days).
3. I'm not referring to hands which are an absolute GF here, but rather hands in the 9-11 point range that are GF opposite 15-17 balanced but not opposite a simple takeout double. These hands have no bid in your system.

You seem to be gambling rather heavily that opponents will run after 2♠-X when responder is short in spades; I've found this is almost never correct as there is rarely a better spot at the three level and opponent in fourth seat may not pass (especially given your style of X, he will often not know to pass when it's right). Even playing a style with relatively free-wheeling five-card preempts it's rarely right to run in direct seat in my experience (passout seat is a different matter of course).

[nullve]

 awm, on 2020-October-21, 10:19, said:

3. I'm not referring to hands which are an absolute GF here, but rather hands in the 9-11 point range that are GF opposite 15-17 balanced but not opposite a simple takeout double.

Ok, that makes sense. Sorry.

 awm, on 2020-October-21, 10:19, said:

These hands have no bid in your system.

True.

 awm, on 2020-October-21, 10:19, said:

You seem to be gambling rather heavily that opponents will run after 2♠-X when responder is short in spades; I've found this is almost never correct as there is rarely a better spot at the three level and opponent in fourth seat may not pass (especially given your style of X, he will often not know to pass when it's right). Even playing a style with relatively free-wheeling five-card preempts it's rarely right to run in direct seat in my experience (passout seat is a different matter of course).

I agree that it's rarely a good idea to run in direct seat if partner can have (but doesn't promise) six spades. But 2♠ could also be be Muiderberg (5S4+m), "preempt with exactly five spades" (quite popular in Norway), Velociraptor (4S5+m),...