nullve

Why would you pass 1♣ with any of these hands?

nullve(N)-nullve(S): 1♣(1)-1♥(2) 2♦(3)-2♠(4) 3♣(5)-3♦(6) 3♥(7)-3♠(8) 4♣(9)-4♠(10) 5♣(11)-5♥(12) 5N(13)-6♣(14) 6♦(15)-P (1) NAT(ish) unBAL or 11-13/17-19/23+ BAL (2) "0+, 4+ S". 0-3 H unless GF values. (3) "19-21 unBAL" (ART) (4) GF relay (5) "5+C(3)4+D" (6) relay (7) 2245, 6C4D(21), 8+C3(!)D or 6+C4+D0S (8) relay (9) 18-20 hcp, 0346 (10) Parity Key Card Blackwood agreeing diamonds (11) odd # of key cards, no trump Q (12) ♣K ask (13) ♣K, no ♥K (14) ♣Q ask (15) no ♣Q

Ok :) And I agree with pass.

I'm always puzzled when I see duplicate players use this expression.

I don't think you will find a single good player in Norway who would open 1♦ and rebid 2♦ over 1♠ with J AQxx KJTxx AQx. 30 years ago almost everyone (in Norway) would open 1♦ and reverse into 2♥. Today you'd see at lot of 1N openings.

Possible standard 2/1 auction if South doesn't know how to transfer to diamonds: 2N(1)-4♦(2) 4♥(3)-4N(4) 5♦(5)-5N(6) 6♣(7)-7N(8) P (1) 20-21 BAL (2) transfer to hearts (!) (3) forced (4) RKC(♥) (5) 1 or 4 key cards (6) king ask (7) ♣K (8) contract

Against humans: 3♣ Robot bridge on BBO: 4N Pass is more preemptive than 3♣? :unsure:

My favourite defence against Multi 2♦: Treat it like Weak 2♦! So pass.

It looks like the 1♣,...,2♣ openings can more or less be obtained from classic Precision's 1♣,...,2♦ and 2N openings by first shifting ranges upwards by one (if BAL) or two (if unBAL) points so that 1♣ = 18+ any 1♦ = 12-14 BAL OR 12-17, unbalanced with either 5+ D, 4D5C, 4D(441) or (41)35 1M = 12-17, 5+ M 1N = 15-17 BAL 2♣ = 12-17, either 6+ C or 5C4M 2♦ = 12-17, "4415 minus 1 card" and then moving * all 4M3-OM hands from 1♦ to 1♣ * all 2245/(31)45 hands from 1♦ to 2♣ * all 4414 hands from 2♦ to 1♦ * all 4405 hands from 2♦ to 2♣ * all (BAL) hands from 2N to 1♣ * all strong (18+) hands that are neither balanced nor 2-suited with at least 5-5 from 1♣ to 1♦.

What do you open with 12-17 hcp and 4414 shape? (1♦, I guess, but then I have a question for you.) Or 12-17 hcp and 4405 shape? (1♦ or 2♣?)

Note to self, mostly:

What are Opener's rebids over 1♣-1♠?

1N

But e.g. so what do you do with 18+ and (5422)/(5431)?

Then what is your opening with 12-17 hcp and (31)45 shape? (I assume you treat 2245 as balanced.)

What are your other opening bids?

https://bridgewithdan.com/wp-content/uploads/2019/07/WEAK-NOTRUMP-SYSTEM-Kokish-Kraft-Jan-2008.pdf https://bridgewithdan.com/wp-content/uploads/2019/12/Martel_Stansby.txt

Again, the weak raise (~ 5-7 total points (not necessarily 5-7 hcp)) is only included in 1M-1N; 2m-2M. And the constructive raise shows ~ 8-10 total points (and not necessarily 8-10 hcp).

1. 1M-1N; 2m-2M contains, but does not exclusively show, the weak raise (~ 5-7 total* points, 3(+) M). Responder may also be showing preference with ~ 5-9 hcp and 2M3-C, even so-called false preference with ~ 8-9 hcp and 2M4C. 1M-2M is a raise with ~ 8-10 total* points. 2. More precisely, Responder is showing ~ 11-12 total* points and 3 M. 3. 1M-1N; 2m-2R(R<M) needs to be used more flexibly than this now that 2m can be on a 3c suit (or even doubleton in the case 1♥-1N; 2♣) You forgot that the most common hand type, which is (new) 3. ~ 5-(bad)12 hcp (good enough for a positive response, not quite good enough for a GF 2/1 response), 2- M and if M=♥ then 3- S spades. * Here total points include support points.

So exactly how is the 2♠ overcall defined in your systems? What do the follow-ups look like?

EW system = ?

https://blog.bridgebase.com/2020/04/29/video-t-walsh-by-gwnn/

Even in the version of T-Walsh where 1♣-[1M-1]; 1N = 18-19 BAL, 2-3 M it's common to play 1♣-1♠; 2N = 18-19 BAL, although 2N may already be too high opposite a subpositive hand such as xxx-Kxx-xxxx-xxx. In these influential notes Fallenius-Welland describe an interesting alternative: to switch Opener's 2♦ and 2N rebids so that (in a system with 15-17 NT) 1♣-1♠; 2♦ = 18-19 BAL and 1♣-1♠; 2N = a diamond reverse. Then it's possible to get out in 2♦ after 1♣-1♠; 2♦-P, e.g. with 18-19 BAL opposite 3 hcp and 3352. Another and IMO vastly better alternative (one that ought to be part of a future Standard T-Walsh!) is helene_t's suggestion in this post where the range of the 1N response plays a crucial role. Using her trick (I'll call it 'Helene's Trick' until she objects :)), the 1♠ response exludes hands on which Responder would at least want to invite 3N opposite 18-19 BAL (or 18-20 BAL in helene_t's post) but definitely stop in 1N opposite 12-14 BAL. Those hands are instead what the 1N response is for. Using Helene's Trick it's of course possible to include balanced 20 counts in 1♣ and play 1♣-[1M-1]; 1N = 18-20 BAL, 2-3 M 1♣-1♠; 1N = (12-14 or 18-20) BAL. Or one can open 1 hcp lighter on balanced hands than in standard 2/1 and play 1♣-[1M-1]; 1N = 17-19 BAL, 2-3 M 1♣-1♠; 1N = (11-13 or 17-19) BAL 1N = 14-16 BAL. EDIT: I just came across this post from 2010 where zenko describes something very similar to Helene's Trick.

It is possible to combine T-Walsh (aka transfer responses to (a natural or short) 1♣) with a completely standard (5533) opening structure. (See e.g. this convention card belonging to young Norwegian internationals Grude-Bakke.) But some like to open 1♣ with 18-19 BAL a little more often than in standard. In the Norwegian BOA system, for example, 1♣ is also opened with 2443 and 4243. And I mentioned in another thread that Brogeland-Lindqvist, perhaps inspired by the (locally very influential) BOA system, open 1♣ also with 4342 in their otherwise natural 5542 system. But opening 1♣ on more strong balanced hands, especially hands with only two clubs, puts extra pressure on Responder who no longer has an easy pass on subpositive hands without an actual club suit. Of the two dominant T-Walsh styles that mikeh described, the one where 1♣-[1M-1]; 1N = 18-19 BAL (or 17-19 BAL in an opening structure with 14-16 NT), 2-3 M, is undoubtedly the one better suited to handle responses on subpositive hands, because the bidding can now go e.g. 1♣-1♦* 1N**-P * 4+ H ** 18-19 BAL, 2-3 H instead of 1♣-1♦* 2N**-P * 4+ H ** 18-19 BAL, 2 H with, say, 18 hcp and 4234 opposite 3 hcp and 3442; and either 1♣-1♥* 1N**-2♠*** P * 4+ S ** 18-19 BAL, 2-3 S *** to play or 1♣-1♥* 1N**-2♥*** 2♠-P * 4+ S ** 18-19 BAL, 2-3 S *** transfer to spades instead of (say) 1♣-1♥* 2N**-P * 4+ S ** 18-19 BAL, 2 S with 19 hcp and 2335 opposite 2 hcp and 5341.