[Kungsgeten]

I like our Swedish club system (except the 2♣ opening), but it isn't very aggressive (15-17 NT, five card majors, Mexican 2♦, weak twos, two-suited weak 2NT majors/minors). I've been thinking about the possibilites of playing a different structure at favourable vulnerability. I'm not sure it is worth the extra memory load, but it is always fun with thought experiments.

I'm considering a strong diamond structure. Why strong diamond instead of strong club? Because of system regulations we could not play a nebulous diamond, since the Swedish club system already has the nebulous 1♣ bid and the artificial 2NT opening. We could however play a strong diamond with a nebulous club without us going over the "artificiality limit".

So how would you think about designing a strong diamond system only played at white vs red? The most obvious choice would probably be Magic Diamond, but I think that may be too much of a memory burden since it is very different from the main system. I've looked at awm's strong diamond systems, which seems playable but perhaps the 2m openings (6+ minor) are too infrequent if one of the goals are to put pressure on the opponents? One idea:

1♣ = 13--15 NT or 13--15 unbalanced without 5-card major.
1♦ = 16+
1♥♠ = 5+ major, 10--15
1NT = 10--12
2♣♦ = Fantunes style, 9--12 unbalanced with 5+ minor.
2♥♠ = Weak.
2NT = Weak. 5-5 minors or majors.

The 1♣ opening seems pretty bad, but it is a tight range and starts at a low level. Would most likely do okay without interference, but the contested auction could get messy.

[nullve]

Maybe

1st seat NV (vs. V):

P = "0-10" (rules of 7-18), unsuitable for 2♣+, guaranteeing 2+D2+C [0 dots]
1♣ = "10-15" (rules of 9-24), unbal. and either 4-S4-H or 5M6+m / 14-16 bal. [3 dots]
1♦ = "16+" (rule of 25+), unbal. / 17+, bal. [0 dots]
1M = "10-15" (rules of 19-24), 5+ M, unbal., no longer side suit [0 dots]
1N = "11-13" (rules of 19-21 if semibal.) [0 dots]
2♣ = Multi: "0-9" (rules of 9-18), either 6M3-OM or 5M3-OM4+m [3 dots]
2♦ = Ekren: "0-10" (rules of 8-18), 4+S4+H [1 dot]
2♥ = Velociraptor: "0-9" (rules of 9-18), 3-S4H5+m [0 dots]
2♠ = Velociraptor: "0-9" (rules of 9-18), 4S3-H5+m [0 dots]
2N = 23-25 bal. [0 dots]
3♣+ = NAT, modern aggresive style¹ [0 dots]

2nd seat NV (vs. V):

Same as in 1st seat except that

* Pass doesn't promise 2+D2+C
* preempts start at "4" (rule of 15).

3rd seat NV (vs. V):

Same as in 1st seat except that

* Pass doesn't promise 2+D2+C
* 1N is "14-16" while 1♣ is opened with "11-13" (bal./semibal.)
* the upper point limit for preempts is "12" (rule of 21), which in turn affects the 1♣ and 1M openings.

I think your 1♣ opening looks good btw. Because the range is so narrow (13-15), you don't need 2N by Opener as Good/bad and can therfore use it as "two places to play", which solves what I think is one of the main problems with my 1♣ structure: how to bid 9-14 hands with 5D5C in competition.

¹ But opening 3m is mandatory with 0-9, 6m1Om33 (or skewer) in order for Pass to promise 2+D2+C.

[Kungsgeten]

You are correct about the dots, but if we want to keep our 2NT opening, that in itself is 2 dots. Ekren would be possible, but a multi would not. Ofcourse the 2NT opening could change to natural in other positions too, if there's enough gain to be had. We're not really fans of the ultra-aggressive "bid on anything" style. Another variant, if we were to remove our 2NT opening, could be "strong diamond precision":

1♣ = 13-15 NT / Unbal with 4+ diamonds / Unbal with 5 clubs and 2+ diamonds.
1♦ = 16+
1M = 10--15.
1NT = 10--12.
2♣ = 6+♣, 10--15.
2♦ = Weak multi.
2♥ = Three-suiter, short diamonds. 10--15.
2♠ = Weak, at least 5-4 minors.
2NT = 19--20.

Or more close to our current structure:

1♣ = 13--15 NT / Unbal with 4+ diamonds, 10--15 / Any 4441, 10--15.
2♣ = 5+♣, 11--15.
2♥ = Weak, at least 5-4 majors.
Rest = As above

[PrecisionL]

Consider 1M = 8-12 hcp? That's what we used for one season of playing a strong diamond system.

[straube]

I've heard of folks who played strong club when the opponents were V and 2/1 when they were NV. The idea was to show suit information faster when the opponents were more likely to overcall. A strong diamond opening is much more cramped than a strong club opening, so I would be thinking to play it when the opponents are NV and likely to overcall anyway. 1C (1S) and 1D (1S) leave us the same amount of bidding room. Curious why you're thinking of playing 1D at favorable.

[Kungsgeten]

PrecisionL, on 2016-June-01, 06:48, said:

Consider 1M = 8-12 hcp? That's what we used for one season of playing a strong diamond system.

That's about the range for Magic Diamond. They use 1♣ as 12-16 unbal or 15-17 NT and 1♦ is 17+. We used to play a two-way forcing pass system using this catch-all club opening and weak Moscito-style transfer openings. However I feel that this may be too far from our current methods.

straube said:

Curious why you're thinking of playing 1D at favorable.

As I wrote in the OP I think a forcing club/diamond system could provide a more aggressive opening style than our Swedish club, and this aggressive style may be desirable when favourable.

[nullve]

T-Walsh idea¹:

min := rules of 19-21
max := rules of 22-24

1♣: as in my post above

1♣-?:

1♦ = 4+ H, may have longer S unless GF values
1♥ = 4+ S, denies 4+ H unless GF values
(...)

1♣-[1M-1]; ?:

(...)
1♠ = either 2-M4+OM5+m, 1M444 or 3OM5+m4+Om / max, 4+ M, not 4M333
...1N = 0-12, 5- M
......P = min
......2♣ = max, 2-M5+C or 1M444
......2♦ = max, 2-M5+D
......(...)
......2M = max, 4+ M, not 4M333
......(...)
...2♣ = ART, GF except opposite min, 3OM5+m4+Om
......2♦+: no strong opinion except that a bid not higher than 2M has to show min, 3OM5+m4+Om, after which it should be possible to stop in 2M
...2♦ = multi-invite
......2♥/2♠/3♣ = P/C
......2N = ART GF
......(...)
...(...)
1N = min, either 3-S2-M6+m or 2-M5D5C / 14-16 bal., 2-3 M
...P = wanted to play 1N opposite 14-16 bal.
...2♣ = P/C, either 5(+) M or GF values opposite 14-16 bal.
......P = min, 2-M6+C
......2♦ = min, 2-M6+D
......2M = 14-16 bal., 2-3 M
.........P = wanted to play 2M opposite 14-16 bal.
.........(...)
......(...)
......2M+1 = 9-11, 2155 [possible to stop in 2♠ opposite 5+S4+H]
......2M+2 = 9-11, 1255
...(...)
2m = max, 3-S2-M6+m
(...)
2M = min, 4+ M, unbal.
2M+1 = 12-14, 2155 [possible to stop in 2♠ opposite 5+S4+H]
2M+2 = 12-14, 1255
(...)

In addition:

1♣-1♦; ?:

1♥ = 3 H, unbal. / 14-16, 3433
...1♠ = 4+ S
......1N = min, 3-S3H
......2m = max, 3-S3H5+m
......2♥ = 3433
......2♠ = min, 4S3H
......(...)
...1N = 3-S4H
......P = min, 3 H
......2m = max, 3H5+m
......2♥ = 3433
...(...)


1♣-1♥; ?:

1N = as above / min, 3 S
...2♣ = as above
......2♥ = min, 3 S
2♥ = max, 3 S, unbal. / 14-16, 4333


¹ See also http://www.bridgebas...-as-catch-all/.