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Methods of interference over a strong one club opening

#1 User is offline   pescetom 

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Posted 2023-August-15, 13:09

In a recent discussion in this forum, there was discussion of strong 1 opening being vulnerable to aggressive bidding and I mentioned my own current method of aggressive intervention. On reflection this is a subject worth discussion in it's own right (maybe there are previous threads that I missed) so I invite both sides of the battle to have their say.

To set the ball rolling, here are the related posts from that discussion.


View Postfoobar, on 2023-August-14, 10:45, said:

Looks like you are saying that strong openings are vulnerable to aggressive bidding by the opponents? If so, it seems like an issue that affects all strong systems, and this system is no exception.



View Postawm, on 2023-August-14, 15:02, said:

My experience has included getting a lot of good results from opponents who jump in aggressively. The thing is, when opener has a balanced 17-19 (which is easily the most frequent 1 hand type), we are actually ahead of natural bidders, because this is the hand type responder will assume from the opening. I'd expect much better results on this hand type after 1(strong)-3 than after 1(natural or balanced)-3 because partner will always play me for it after the strong club (and can do things like negative double on an eight count and four hearts, or bid 4 on 6-8 points and six hearts, or bid 3NT on a flat 7-9 with a stopper) whereas on the latter auction he must be concerned about the (much more common) weak notrump or minimum distributional club hand.

It's only when opener has a two-suiter that I'll often wish that I was playing a natural system; it's much easier to bid 1(natural)-3-P-P-4 and show both long suits and extras, whereas 1(strong)-3-P-P is more awkward.

But of course defenders don't know opener's hand type when they decide to preempt, and odds are fairly good that opener is balanced (or has a one-suiter, which is easy to handle in competition).



View Postpescetom, on 2023-August-14, 15:42, said:

Not playing a strong club system, I am seeing fairly good MP results from jumping in aggressively over strong 1, playing the opener for a strong NT. With two partners I agreed to bid Multilandy, with the obvious variation that Double shows clubs and 1NT is equivalent to Double. I would be curious to know what those who play these systems think about that, but it seems to work out quite well so far, better than Mathe' which caused them few problems.



View Postmycroft, on 2023-August-15, 09:08, said:

I don't mind double=majors, and play Mathé by preference (wouldn't in a world where we saw enough strong club that we could remember something else reliably). Sure, it's a stupid bid, and gives the opponents more room and... but I have a partner too. And as someone doing a I/N presentation on (playing against) weak NT said, "I actually like Landy. Everything natural, except for 2, which is the hand most wanting to compete - both majors". And if partner has enough of either major to get to 2 or the 3 level - sure, responder will assume that opener has the 17-19 BAL. But negative double into the 4-1 break? or is opener the short in the other major one? or "take the points, find out that 3NT scores better"? Never mind when they don't have it and 500 into 920 comes out.

My goal, having played Precision for nearly a decade, is to get to 2 or higher before opener gets a rebid. Only when it's safe, but still. Any system that makes that harder, to me, is worse than the confusion and lack of cuebids it provides to the opponents. So, for me the problem is the Multi 1 call - now partner needs (not that much, but) something in both majors to push enough (and it still gives them one more call over passing). Not terribly thrilled with the 1M call either - sure it's great when you find the 4-4 fit and raise, it's fine when you can afford to pass it, but when partner has to go looking for the minor, the strong club's ears hear "misfit"...

I also believe that if you're going to make a "confuse the opponents" call, it has to be one that is easily passed. That was my argument against Suction (in both places it's played, frankly). "bid the one suit you're guaranteed to not have" = "pass and resolve the confusion, if you don't have something you want to get out straight away". It would also apply to 1 "one major", except that most will do the "split the 1 call into 'bad' and 'okay'" to make their memory easier. Now a *1* "either major" call :-)

But to the original comment that sparked this subthread, I started my local "intro to Precision" class with "So, Precision sacrifices 4 calls (1m, 2m) to get their 1M limited openers. It's worth it." That's a bit of a stretch (the 2 call is really nice when it comes up, and 1 "grunt" actually isn't much of a sacrifice), but not actually false.

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#2 User is offline   foobar 

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Posted 2023-August-15, 13:25

This thread has a lengthy discussion on interference methods.. IMO, most Suction variants, with the exception of Psycho-Suction aren't very effective. Also, interference below 1 (1N?) usually doesn't cause much heartburn (except maybe knocking us out of relays).
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#3 User is online   DavidKok 

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Posted 2023-August-15, 14:52

I've commented on that other thread as well, but maybe I can summarise it a bit here to keep the discussion going. For more detail please check out my comment on the link above.

  • I think bidding 1 or 1 does quite a bit of damage, claims about not taking up bidding space notwithstanding.
  • Personally I've scored very well when fourth hand got just a bit too active. People always talk up bidding to 2 or 3 or something as fast as possible, when really it's often putting your head on the chopping block for no good reason. Trust partner to have bid to the limit of their hand, and make a normal, not a crazy, raise. You don't have to stretch.
  • Quite a few strong clubbers use archaic and questionable defenses to interference, which really skews the data on what works and what doesn't.
  • Overcalling 2 or 2 natural (frequently on a 5-card suit, wide range) is devastating to the opening side. It pays to bid this frequently. Using this as some artificial call has a correspondingly grand opportunity cost.
  • All of the really weak (or 'garbage') preempts, most notably the multi-meaning ones designed to sow confusion, are not the killer weapons they may seem.
  • The 1 opening is not the most important part (by far!) of a strong club system, and I don't think it is worth worrying too much about it. It pays to disturb it, but for e.g. Precision you can win a lot more IMPs by making good competitive agreements over their 1 than over their 1. I also think most response systems to a strong club aren't that amazing to begin with, so it's not even clear you're headed for a loss if you leave them be.


To finish, a longer remark. I think natural (but wide ranging, can be weak) overcalls can wreak a lot of havoc. Swapping one of those out for some conventional bid comes with a significant opportunity cost. If you want to assign conventional meanings to bids I think double, 1, 1NT and possibly 2NT are some good bids to replace, as these have little to no competitive natural use. The biggest downside of conventional interference is that it tends to be forcing (or, at least, unsafe for advancer pass a double) giving the opponents two chances to find the right bid. This makes them significantly worse competitively. If you want to play some fun, possibly multi-meaning and conventional system of interference I'd start by replacing the bids that have no great natural meaning anyway. If you start replacing natural calls I'd look for something that has lots of bids that, while conventional, can frequently be passed. Frankly I think most of the artificial interference systems are not that good, that it's not that important to get this right when facing a strong club system, and that the general approach of aiming to take away lots of bidding space quickly is worse than it seems. I suspect quite a few of these systems (e.g. CRASH and Suction) are played mostly because they are fun, and the auction doesn't come up enough to determine whether or not they are good (I think they're worse than natural, but as stated above it won't cost you much either way).
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#4 User is offline   mycroft 

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Posted 2023-August-16, 11:13

re: putting your head on the chopping block: I am still remembering a (limited) National event I played at where it went 1-1NT-X-AP. Vulnerable. And we took it for 1400. Like all preempts, if you're not offering a top *sometimes*, you're not pushing them around enough the rest of the time.

Oh, the result? An almost zero, on a 25 top (the field was in 6=, for 1430).

I do see David, and awm's comment of "assume partner has balanced minimum", and "sometimes you don't really have much choice apart from taking the points". And again, when it turns out right (at MPs), it's spectacularly right (and, as above, when it's wrong, it's spectacularly wrong). At teams, interestingly enough, much less so (so you go -800 into a vul game? next time it'll be -200 , or +100 when they try 4 because they didn't feel comfortable "taking the points". And maybe you get it back next hand on 3= into 3-1, or they're on the wrong side of 1 on good 10-x-3 on shapely 4-x into your game. Which usually is a huge plus for the strong club players, but usually != always, and this time it's "800 into vul game").

But at MPs, if you let them use their full system, they'll get to the right contract. Especially when there's a potential slam. So it's likely that your "don't push 'em around" baseline is well short of 50%. So it has to work less often than it fails to break even, because you lose less when it's wrong than you win when it's right.

I also absolutely agree that the best of us can use the interference to make their results even better; and that it's *very easy* to go overboard, and the strong clubbers have more experience handling this situation than you do defending against it (even if you're a strong clubber yourself!) But I'm still looking at "if they get to use their system, we lose to the field" over there...
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)
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#5 User is offline   foobar 

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Posted 2023-August-16, 11:51

View PostDavidKok, on 2023-August-15, 14:52, said:

[*]Quite a few strong clubbers use archaic and questionable defenses to interference, which really skews the data on what works and what doesn't.


Can you elaborate on the above? AFAIK, most (many?) Precision players on this side of the pond play something like X = 5-7 any, with the cheapest bids natural and GF. Systems like IMPrecision that use more sophisticated approaches like 2-level transfers are an exception.

BTW, it looks like Nystrom-Upmark use P = "any non semi-positive hand", with X and non-jumps as GF.
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#6 User is online   DavidKok 

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Posted 2023-August-16, 12:31

View Postfoobar, on 2023-August-16, 11:51, said:

Can you elaborate on the above? AFAIK, most (many?) Precision players on this side of the pond play something like X = 5-7 any, with the cheapest bids natural and GF. Systems like IMPrecision that use more sophisticated approaches like 2-level transfers are an exception.
This is exactly the defence I'm referring to. Pass = weak or trap pass, X = 5-7 any, bids = natural GF is quite poor. By opening a strong 1 we are behind the field by not showing any shape in what is likely to be a competitive auction. Following that up with a second non-shape-showing bid may make the gap insurmountable.

By frequency the 0-4, 5-7, 8+ brackets don't make that much sense. If I plug not-terribly-crazy overcall system on a strong club (overcalling on the 1-level shows 5(+) in that suit and 6-17 HCP, overcalling 2 shows 5(+) and 8-17, with two long suits ties go to the major suit) and condition on no overcall responder has a 0-7 hand 49.8% of the time and a positive response 50.2% of the time. If I condition on some overcall that turns into 28% 0-4, 36% 5-7, 36% 8+. I think the large majority of the time responder will have a hand that is too weak to force to game. What's more, not only is it not that necessary to create a game force at the 1-level or even 2-level (standard bidders have constructive but not necessarily GF auctions starting at the 2-level all the time! In fact, if you ever overcall, you are in one too!), I also think the semipositive 5-7 hands with some shape are most important to show immediately as they can get pushed out the auction if advancer raises. Assigning all the remaining bidding space exclusively to the game forcing hands is great when it's a slam, so-so when it's game (and then it had better be an 8+ versus 16+ game, and not a 5-7 facing 18-19 game) and verging on unplayable when it's a partscore deal. I've also on occasion seen partners respond e.g. 1*-(1)-1 on technically insufficient values 'but I had to to show my spade suit' (which I think shows good judgement - the 1-level is safe and long major suits should be shown whenever possible) and had it backfire when we had a misfit and bid ourselves to a hopeless 3NT on a combined 22-count. There's just no need to be this strict with bids at such a low level.

Personally I think complicated structures in competition, mostly based on 'semipositive or stronger' transfers, are a huge improvement. This way responder gets to show shape on the majority of hands after interference. IMPrecision has a system, I think it can be somewhat improved and also works well over a nebulous diamond, a natural 1m opening (especially a 2+ 1 opening) and possibly in a few more situations, e.g. I've adapted it to hopefully work reasonably well over an unbalanced diamond. It is complicated and depends on the overcall the opponents have made so I won't write it out in full here (if there's interest I'd be happy to start a new thread though), but the main idea is to allow responder to enter the auction with some amount of shape and semipositive or stronger hands quickly, to catch up on the deficit created by the shapeless 1.

More generally I think having dozens if not hundreds of pages of constructive system notes but only a few pages on competitive auctions is backwards. Most auctions these days see competition, and this is also where the difficult choice of game decisions, awkward double game swings and terrible misunderstandings and phantom sacrifices happen. If anything people should spend much more time on refining their systems after interference, and letting responder into the auction after interference over a strong club seems like an obvious place to start.
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#7 User is offline   foobar 

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Posted 2023-August-16, 13:14

View PostDavidKok, on 2023-August-16, 12:31, said:

opening) and possibly in a few more situations, e.g. I've adapted it to hopefully work reasonably well over an unbalanced diamond. It is complicated and depends on the overcall the opponents have made so I won't write it out in full here (if there's interest I'd be happy to start a new thread though), but the main idea is to allow responder to enter the auction with some amount of shape and semipositive or stronger hands quickly, to catch up on the deficit created by the shapeless 1.

I am all ears, and think others will be interested as well.
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#8 User is offline   pescetom 

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Posted 2023-August-18, 10:08

Thanks all for the thoughtful input. I read the entire BW thread and was surprised to see so little consensus between so many good players, including those who play strong club themselves. Something is clearly wrong here and I doubt it is just that the strong club players are trying to convince the rest of us that they are frightened of double for majors (Brer Rabbit and the Briar Patch comes to mind :) ). Maybe David puts his finger on it when he suggests that many strong club players employ questionable defences, which can illude them into thinking that the damage is inevitable and the opposition into thinking this is a near-free lunch.

Getting back to our situation, it looks to me as if our current method of interfering Multi-Landy is not that bad when judged in the light of this thread. It costs us little extra memory load (even less than Mathe' would) as we already play almost exactly the same way over strong NT. The only difference is that here we use double to show clubs (which is a significant weakness, agreed) and 1NT to show 4M5m (which is artificial as suggested). Our 2 is Landy (which is not as safe or effective as showing clubs, agreed), our 2 is Multi (which gives them the usual problems and can be passed), our 2/ are 5M4m (which can be a bit pushy, as Mycroft argues, but then we take the same risks over strong NT), our 2NT is minors 5m5m and all 3 level is natural.

Maybe we could define the natural 1 level bids a lower level of HCP, increasing safety and definition.
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#9 User is offline   sfi 

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Posted 2023-August-18, 17:36

View Postpescetom, on 2023-August-18, 10:08, said:

Thanks all for the thoughtful input. I read the entire BW thread and was surprised to see so little consensus between so many good players, including those who play strong club themselves.

As a measure of how little I am worried about what the opponents play over my strong club, it's not even something I look at when I'm reading through their card before a round. So my advice is pick something that suits you and run with it. The other suggestion I would make is to bid aggressively with shape.
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#10 User is offline   Gilithin 

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Posted 2023-August-20, 08:00

View Postfoobar, on 2023-August-15, 13:25, said:

This thread has a lengthy discussion on interference methods.[/url]. IMO, most Suction variants, with the exception of Psycho-Suction aren't very effective. Also, interference below 1 (1N?) usually doesn't cause much heartburn (except maybe knocking us out of relays).

No need to go external for a thread on this. There are plenty here (example). As mentioned by several posters, you should make sure that X, 1 and 1 represent hands that partner can raise easily when they have an appropriate hand. Aside from that, non-forcing calls are good and multi calls can sometimes be good. Everything else is really just noise.
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#11 User is offline   akwoo 

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Posted 2023-August-20, 14:30

If you want a Suction variant, I've been convinced by Reverse Psycho - a bid shows that suit and the next suit, or the one above that. It's passed (and passed for a disaster) less than usual Psycho but there's enough of a possibility that responder (and the defensive system) has to cater to it. The big disadvantage compared with usual Psycho or even standard Suction is that, on the most common hand type (the one-suiter), it takes up two or one fewer step.


I think my slight preference is natural at the one level, with reverse-psycho-suction starting at 1N (which shows two non-touching suits). But I don't care much and will play whatever partner wants to remember.
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