[pescetom]

With most partners I play a fairly normal 2♣ opening showing either 22+ HCP balanced or a strong unbalanced hand (game forcing in absence of 2nd negative), with suit responses showing a good 5+card suit in a good hand and 2♦ showing any other hand regardless of HCP. We play Kokish and in one partnership transfers but that isn't relevant here.

When opponents interfere with a suit overcall we play that:
- Pass by responder shows a hand that would have bid 2♦
- double by responder is penalty oriented
- suit by responder shows a good 5+card suit in any hand
- double by opener is penalty.

This scheme of handling interference is simple and natural, but it doesn't strike me as very efficient - the opponents offered us two extra bids to exploit, but essentially we have gained only one option (punishment) and no extra information.

Larry Cohen (who is usually up to date and sensible) suggests the following scheme:
- Pass by responder shows a game-forcing hand.
- double by responder shows a terrible hand (0-3)
- suit by responder shows 8+ HCP and a good 5+card suit
- double by opener is takeout.
This scheme exchanges more information, but I'm a bit puzzled all the same. I can see a case for takeout by opener in some conditions, but I'd be concerned if we were unable to punish a rash or unfortunate overcall. I can see why a "terrible hand" warning would be useful if they overcall at 3-level, but not below (opener's rebid of 2NT is non-forcing). Plus the hand strength requirement for responder to show suit is the same as it was without interference, which strikes me as strange.

Any comments from expert players? Is there a better scheme?

[apollo1201]

It seems you don’t use the cue bid and NT (I play the same except X and pass are reversed, X = values without good suit to bid or stoppers).
I play cue = 3-suited (5431 ok) and 2NT stopper with values and GF obviously.

[ggwhiz]

We cater to the 22ish 2nt rebid by opener as the most problematic and perhaps most likely hand for the 2♣ opener.

pass = game force values with no other clear bid
after that double by opener shows the 22ish flat hand but not pure penalty (ie. red vs white)
double = the double negative, 0-4 no A or K

If a penalty is available we always get it and still have max room to find our right strain and level.

[The_Badger]

When I used to play bridge regularly, my partner and myself used:-

Double by responder equals Yarborough(ish) values, you're on your own partner, the 2♣ opener's next bid is usually his final bid
Pass = 3-6 balanced/semi-balanced
Suit = 7+ with aqxxx or ajtxx minimum
2NT or 3NT over 3♣ = 7+ unbalanced, usually shortness in overcaller's suit, but with a poorer 5 card suit or 4441

Obviously it doesn't cater for every situation, but it was ok for general overcalls up to 3♣ over 2♣. I can't remember exactly if we discussed a strategy for pre-emptive - 3♦ or above - overcalls. Think we agreed that 'Pass' was no values, Double was some values but without suit, Suit = some values with a suit. Not ideal, I admit, but there again not many players would interfere over 2♣ in those days for fear of penalty: these days they are bit more bolder.

[pescetom]

 apollo1201, on 2018-August-29, 11:48, said:

It seems you don’t use the cue bid and NT (I play the same except X and pass are reversed, X = values without good suit to bid or stoppers).
I play cue = 3-suited (5431 ok) and 2NT stopper with values and GF obviously.

Correct, our current scholastic defence doesn't use the cue bid or NT by responder.
I agree we should find some use for them.
I'm very wary about responder using NT for anything that is likely to lead to us playing in NT: around here most other pairs will open a flat 22 as 2NT rather than 2♣ and if we are the only pair to wrongside the contract it is just asking for a bottom.
Maybe it would make sense for us to invert your bids, cue = stopper showing and 2NT = 3-suited takeout.
Although of course that begs the question of what to do over direct 3-level interference, where I guess 3NT must show stopper (or maybe half a stopper).

[pescetom]

 The_Badger, on 2018-August-29, 22:58, said:

Double by responder = Yarborough(ish) values, you're on your own partner, the 2♣ opener's next bid is usually his final bid
Pass = 3-6 balanced/semi-balanced
Suit = 7+ with aqxxx or ajtxx minimum
2NT or 3NT over 3♣ = 7+ unbalanced, usually shortness in overcaller's suit, but with a poorer 5 card suit or 4441

So NT is essentially 3-suited takeout as I was thinking above, although it sounds as if you privilege point over distribution.

 The_Badger, on 2018-August-29, 22:58, said:

Obviously it doesn't cater for every situation, but it was ok for general overcalls up to 3♣ over 2♣. I can't remember exactly if we discussed a strategy for pre-emptive - 3♦ or above - overcalls. Think we agreed that 'Pass' was no values, Double was some values but without suit, Suit = some values with a suit. Not ideal, I admit, but there again not many players would interfere over 2♣ in those days for fear of penalty: these days they are bit more bolder.

When playing above club level I am encountering increasingly bold and systematic interference over 2♣, hence my desire to improve our defences. In particular a 3♠ interference successfully nudged us out of a slam in a team tournament recently.
I'm curious as to why you split strategy from 3♦ upwards, rather than from 3♣ or 3♥ ?

[pescetom]

 ggwhiz, on 2018-August-29, 14:23, said:

We cater to the 22ish 2nt rebid by opener as the most problematic and perhaps most likely hand for the 2♣ opener.

pass = game force values with no other clear bid
after that double by opener shows the 22ish flat hand but not pure penalty (ie. red vs white)
double = the double negative, 0-4 no A or K

If a penalty is available we always get it and still have max room to find our right strain and level.

That sounds like a good part of what I am looking for, but I'm not sure I fully grasped what the options are for opener holding 22ish flat after responder's pass: when would he bid NT rather than double? And what happens when interference gets higher?
Maybe you could comment these examples if you have time:
A. 2♣ (2♠) p (p) DBL (p) ?
B. 2♣ (2♠) p (p) 2NT (p) ?
C. 2♣ (2♠) p (3♠) DBL (p) ?
D. 2♣ (2♠) p (3♠) 3NT (p) ?
E. 2♣ (3♠) p (p) DBL (p) ?
F. 2♣ (3♠) p (p) 3NT (p) ?
Thanks.

[Stephen Tu]

For many years I played the standardish double = bad hand negative; I have decided that I really don't like it. What the hell is opener supposed to do when double = bad hand any shape? He can't know when to leave it in when it's 0-4/5 trumps any shape, and how does he know what suit to bid, with the most common hand type which has to be 22+ bal? With that hand mostly OPENER wants to takeout double and have responder bid his best suit/ pass for penalties/bid 3nt. But if responder doubles, opener no longer has his takeout double available.

In every other competitive situation, people have mostly settled on takeout/negative doubles, so why all of a sudden do something different and unfamiliar after 2c?

so after 2c-(2s), I would play responder's double as takeoutish shape, GF, pass = trapping or bad hand. After pass, and opener's reopening double, just treat it as if overcaller had *opened* a weak two, and opener with a huge hand made a takeout double, with just range adjustments knowing that the doubler has a huge hand. Like Lebensohl could apply, except now it's REALLY broke, and you just bid directly 3 level FG with a trick.

So basically I am treating the auction as responder as if opener opened a 22+ 2nt and opp overcalled (though of course opener will show suit of his own with distributional opener), and if responder passes, treat as if you are defending vs a preempt except for the known extra strength.

[kuhchung]

++ for Stephen Tu's post!

[rmnka447]

The most important thing is have an agreement as to what double and pass means over interference. Double values/Pass weak or Double weak/pass values are both workable and have their plusses and minuses. Suit bids ought to show relatively good holdings in the suit and values. As long as you do that, you should have a good chance of handling the interference.

If you want to agree to something more sophisticated OK as long as both partners can remember the agreements and remain on the same page as to how they'll use them. Remember these may not come up often enough so that they will remain fresh in both partner's minds, especially when under pressure at the table. Rodwell-Meckstroth may be extraordinary in having several hundred pages of bidding agreements that they have and can remember. For us mere mortals, if that is beyond us, it's better to have more detailed agreements on things that come up fairly frequently and rely on just some basic agreements on things that come up once in a blue moon. Do what works best for you.

[pescetom]

 Stephen Tu, on 2018-August-30, 11:21, said:

For many years I played the standardish double = bad hand negative; I have decided that I really don't like it. What the hell is opener supposed to do when double = bad hand any shape? He can't know when to leave it in when it's 0-4/5 trumps any shape, and how does he know what suit to bid, with the most common hand type which has to be 22+ bal? With that hand mostly OPENER wants to takeout double and have responder bid his best suit/ pass for penalties/bid 3nt. But if responder doubles, opener no longer has his takeout double available.

In every other competitive situation, people have mostly settled on takeout/negative doubles, so why all of a sudden do something different and unfamiliar after 2c?

so after 2c-(2s), I would play responder's double as takeoutish shape, GF, pass = trapping or bad hand. After pass, and opener's reopening double, just treat it as if overcaller had *opened* a weak two, and opener with a huge hand made a takeout double, with just range adjustments knowing that the doubler has a huge hand. Like Lebensohl could apply, except now it's REALLY broke, and you just bid directly 3 level FG with a trick.

So basically I am treating the auction as responder as if opener opened a 22+ 2nt and opp overcalled (though of course opener will show suit of his own with distributional opener), and if responder passes, treat as if you are defending vs a preempt except for the known extra strength.

That makes a lot of sense and I like it because it is similar to how we do everything else. But if I understand rightly, we wouldn't be able to punish when neither of us is short in the opponent's suit, which is a concern. I also wonder just how likely it is that opener with the points has no stopper and responder has a full one: probably it is more likely half and half in which case it would be useful to be able to negotiate this.
Still thinking about this one.

[pescetom]

 rmnka447, on 2018-August-30, 13:14, said:

The most important thing is have an agreement as to what double and pass means over interference. Double values/Pass weak or Double weak/pass values are both workable and have their plusses and minuses. Suit bids ought to show relatively good holdings in the suit and values. As long as you do that, you should have a good chance of handling the interference.

If you want to agree to something more sophisticated OK as long as both partners can remember the agreements and remain on the same page as to how they'll use them. Remember these may not come up often enough so that they will remain fresh in both partner's minds, especially when under pressure at the table. Rodwell-Meckstroth may be extraordinary in having several hundred pages of bidding agreements that they have and can remember. For us mere mortals, if that is beyond us, it's better to have more detailed agreements on things that come up fairly frequently and rely on just some basic agreements on things that come up once in a blue moon. Do what works best for you.

I agree about avoiding unnecessarily detailed agreements of course, especially as I have to play this stuff with multiple partners and each has his own tolerance for system notes, plus I have the additional load of remembering differences.
And yes I think we will limit Responder to Double and Pass, plus Suit of course.
I am thinking about something like this:
- Suit by Responder shows a good 5+card suit, normal developments follow
- Double by Responder shows 5 points or a holding in opponent's suit, FG. Opener then bids:
Pass = punishment
2NT = takeout 22+, Pass/raise with half a stopper
3NT = 22+ NF, with stopper
Suit = as after 2♦
- Pass by Responder shows a hand with no better bid. Opener then bids:
Double = takeout 22+
2NT = 22-24 NF
3NT = 25+ NF
Suit = as after 2♦.

Just an idea for now, comments are welcome.

Thanks anyway to all who replied here.