DavidKok, on 2020-September-20, 12:29, said:
I recently made a mistake about the meaning of a redouble (by me) on the auction 1♥-(X)-?. I was under the impression that generally an XX here shows around 11+ points and shows values in all unbid suits, denying heart length or an own long suit. This sets up penalty doubles for both partner and me, even on the 1-level. After the auction I learned that not only can a redouble be played as any 11+-point hand (intending to jump in ♥ on the next round with a fit?), but also this is actually the explanation in my system notes. Oops..
I will answer questions with an American bias; I don't know standard practices in the Netherlands or really any other country. My learning has been mostly from American and British authors.
The modern advanced/expert trend is to *not* use natural bidding after 1M-x, transfer schemes have a lot of popularity. There is a lot of variation in these, some start transfers at 1nt (xx old fashioned, 1s natural F1), some at 1S, some with redouble. Some give up a way to show a natural 1nt response, some don't; some give up on the old fashioned head-hunting redouble (have to pass then double), some don't, etc. Needs discussion on the exact variant to be played.
Whether you play xfers or not, usually *FOUR+* cd major raises are excluded (weak 3M, LR+ 2nt aka "Jordan" aka "Truscott"). But strong 10/11+ *three* cd M raises, there is still variation. Many people still include some of these in redouble (partner will support later instead of doubling opps/bidding NT/bidding new suit), some people prefer to exclude them (putting them into some transfer raise in some fashion). If playing strictly natural and not transfers I kind of think you have to put some of these good 3cd raises into the xx.
So xx shows 10+ (or maybe 11+ if you are playing lighter openers), and values/length in 2 unbid suits (not necessarily all 3, you are hoping partner can double the other one), OR 10/11+ hands with 3 cd support (if agreed).
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After 1♥-(X)-?, are 1♠/2♣/2♦ forcing (if you play these as natural)?
Maybe 60 years ago, all natural bids were NF, you had to redouble first to force. Then good players figured out this was terrible opposite preemption, and made 1 level bids forcing but 2 level bids still NF. Then good players decided 2 level NF is still bad and switched to xfers to start showing the suit immediately. In some countries people play 2 level bids as F1, but it's non-std in America.
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After for example 1♥-(X)-XX-(2♦); P-(P)-? is 2♥ (strongly) invitational with around 11 points and three-card heart support, or does it show mild preference to hearts over defending diamonds if partner cannot double?
For me, partner should assume 3 cd LR hand, but occasionally you might turn up a trump short, oh well, he can try to cater to that if he wants to bid game and there might be somewhere else to play. I prefer having 3H available as a force, and being able to invite and stop at 2. But this requires discussion as obviously the posters above me interpret differently.
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If partner bids a new suit, for example 1♥-(X)-XX-(1♠); 2♣-(P)-? is this new bid forcing? Presumably passing 1♠ was forcing, so bidding with weak hands seems questionable (as it solves the opponent's problems).
Traditionally this is a weak distributional hand, that would never want to defend 1S-dbl, and is NF. Strong hand needs to jump, or pass and bid later.
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After 1♥-(X)-?, what would a jump shift (2♠/3♣/3♦) show? Forcing fitjumps?
Could be fit jump, weak jump shift, or mixed raise by agreement.
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Assume you also double with shapely hands (perhaps you don't have a choice with strong hands, with direct bids NF and jumps as fitbids). After 1♥-(X)-XX-(2♠); P-(P)-? is 3♣ forcing (and therefore practically game forcing)? Do you play Good/Bad 2NT, or some flavour of Lebensohl, here? 2♠ is explained as preemptive.
If you are forced to xx with forcing clubs, then 3c is logically forcing. I don't play GB2nt here.
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What is your personal preference for the meaning of redouble after 1♥-(X)-?
Does any of this change if partner opened 1♠ or 1m instead?
Do any of your agreements depend on the vulnerability?
I use the traditional meaning of xx, any vul, denies 4+ fit for major or 5+ fit for minor, but can include 3cd M raise hands, and use xfers over 1M-x starting with 1nt, in most of my partnerships.