maximal double, an illustration. From a jcrecch lesson

[kenberg]

The following hand came up yesterday (Thursday)

  AKT83 
  8 
  QJ6 
  AJ63

Not a bad hand. You are non-vul against non-vul opponents, it's a lesson hand but I think the setting was imps, it's two passes to you and you begin with 1 . The auction turns competitive:

  P      P    1     2
2   3    ?


What to do?    There is a convention for handling this, the maximal double, but I decided to take the bull by the horns. I frequently get gored, but I recover fast. So I bid 4 . My thinking was that their values seem to be in hearts, so I suppose whatever values pard has are elsewhere, that figures to be good. Well, it worked. We have a 9 card spade fit, spades are 2-2, everything is swell. They have an 8  card heart fit so LOTT says their should be 17 total tricks if we add the tricks in a spade contract to the tricks in a heart contract.  LOTT is off by one, as it often is. Here are the hands:

http://tinyurl.com/ybwv3efn


We could probably all agree that ten tricks requires a little luck. 



Now to the Maximal Double. As I have mentioned before, Mike Lawrence has a disk on conventions. He presents an auction:

1     2     2     3
 ?

He then presents two hands, one of them has a six card heart suit and minimal values, the other has a five card heart suit and enough values so that playing in game seems like a possibility. An important feature is that their is no suit between and , just as in my case there is no suit between and . In the Lawrence hand, 3 would be to play, absolutely not invitational, a double of 3 is not penalty, it's an invit to 4 .  If the opponent's had been bidding clubs, 1     2     2     3 , then this maximal double is off. The double of 3 would be penalty, a bid of 3 over 3 would be the invitation to 4 .



Had we been playing that agreement with my hand, I would have doubled 3 , inviting game in , and partner would presumably have taken a realistic view that 3 is high enough. Yes it makes 4, but if you just look at my hand and partner's, I doubt that you really want to be there. You can develop two ricks, and you have one trick, but you need 7 more to make 4 . and before they take 4. It works. Nice of pard to have four trumps, and nice of trumps to split 2-2.

There are a lot of conventions out there, and a lot of them are played in different ways by different people. I like the Lawrence disk, but whether it's that or something else there is a lot to be said for  having something written somewhere and then agreeing we play convention X as it is written up in that source.

And, to be repetitious, these lesson hands can be very useful.

[bAbsG]

Ken - is this what is called an OBAR bid?  Opponents bid and raise the suit just below your suit so that no HSGT bid is available.

Not sure how many people use these but they are sure helpful!

[kenberg]

It is related, or at least sort of.

For OBAR, let's go to  Larry Cohen at   

https://www.larryco.com/uploaded/product/44b5ae8f-5e4c-4256-8921-5d2645c54591.pdf

Here is the idea of OBAR. Well as I understand it

 Suppose the bidding begins 1 - Pass -2 - ?


LC suggests bidding 2 with very little. The example hand that he gives is KQT97 / 73 / JT85 / 84.

The logic is this.  For the moment, imagine you are in second chair rather than fourth chair, and let's suppose you think that this hand is a bit light for a direct overcall of 1 over 1 . But maybe, with you still in second seat,  it goes 1 - Pass -2 M - Pass - Pass - ?  You have another shot, the opponents have found a fit but are stopping at 2 , so maybe you balance with 2 . Maybe you do, let's suppose that you would. OK. Now we put you back in fourth chair with this hand and the auction goes 1 - Pass -2 - ?. You reason, or at least LC reasons: Well, if I were in 2nd chair and if this were passed around to me I would balance with this, so m maybe I should do it now anyway. If my LHO was about to pass, then this is just like being in the pass out seat, and if he was not going to pass he probably will go on ni hearts anyway rather than saw me off at the 2 level.

So the OBAR idea is to" balance when you are not in the balance position".

I have not so much bought into this. Of course if it were just a matter of listening to me or listening to LC, you should of course listen to me.    No, you should listen to LC. But I am not sure that this is all that OBAR has all that wide a following. Notice that with the LC hand, you can reasonably believe that you would (probably)  like a lead if they do go on in , which they probably will. So it does have that going for it.

So OBAR is an aggressive action against opponents who have opened the bidding and raised.

Now if the auction begins 1 - Pass - 2 - 2   what should a double by opener be? The thing is, these super aggressive OBAR bids are often at the 2 level since coming i at the 3 level in a live auction on not much is not appealing.  Still, there will be times when the auction begins - Pass - 2 - 3 .  Now we are at the point where they have crowded us out of bidding room.

Back to Mike Lawrence. In his section on the Maximal Double he recommends keeping  1 - Pass - 2 - 3 - X as a penalty double!  Compare this auction with 1 - 2 - 2 - 3 - X. In this latter auction, you and the opponents both have a fi, and this means that the priority is likely to be distinguishing between a 3 sign off (bid 3 ) and an invit to 4 (make the Maximal Double). In the auction - Pass - 2 - 3   the opponents might or might not have a fit, perhaps they have just waltzed their way into trouble, and ML recommends keeping the Penalty Double as an option. I am pretty sure you could find expert opinion who disagree. You can't have everything. ML thinks that if we have a heart fit and they are known to have a diamond fit, we rarely want to hi 3 for penalty. But if we have a fit and they only might have a fit, then keeping the penalty option sounds right.

Which gets me back to an earlier point. Maybe ML is right about keeping the penalty meaning in this case, maybe he isn't, but how to decide. I think that there is a lot to be aid for just picking  a source and saying "Let's do it his/her way".

An aside, maybe relevant: It is often noted that if one side has a fit then so does the other. Well, sort of. Suppose opening side has an 8 card heart fit. The opponents have 26 card between them, 5 of their cards are hearts, so 21 are non-hearts. It's possible that they have three 7 card fits. If the opening side has a 9 card fit then the opponents have 4 hearts and 22 non-hearts, so then yes, there must be an 8 card (or better) fit somewhere. 
But now back to the auction  1 - Pass - 2 - 3 . Opening side might have only an 8 card fit so there is no guarantee that opponents have an 8 card fit anywhere, and, moreover, even if they have an 8 card fit it might not be in diamonds!. So the penalty X now looks a little more useful. Compare with 1 - 2 - 2 - 3 . Now they almost certainly, unless they are truly nuts,  have an 8 card fit, quite possible a 9 card fit, and so now we want to decide whether to sign off in 3 or make a game try. Hence the Max Double. 

This answer got a bit long!

[bAbsG]

Thanks Ken  Well explained.   

[Curls77]

Indeed, ty Ken, so well explained

[kenberg]

Thanks. Let me push a little more on a general thought. I mentioned that Mike Lawrence lists when, in his view, Maximal Doubles should apply and when the X should retain its natural meaning of penalty. There is simply no way around this: Different people have different ideas of what it means to play a named convention.

A recent example from a f2f game. We started 1 - 1 - 2 - 2 . Partner alerted and, when they asked, explained it as new minor forcing.  Some play 2 is NMF after 1 - 1M - 2 , some even play 3 as NMF after 1 - 1M - 2 , but I prefer not to and I thought we had agreed not to. He rebid 3 and I had no trouble passing and yes I did have five hearts and a 10 count, and yes I was hoping that partner might bid 2 over my 2 so no real harm was done.  There would have been more potential for trouble if I had spades instead of hearts. Imagine  1 - 1 - 2 . What would 2 be? Those who play that  1 - 1 - 2 - 2 as NMF usually (and there is that "usually" again) play that  1 - 1 - 2 - 2 is non-forcing since responder did not opt for the artificial 2 . But I, not playing NMF over 2 ,  play that  1 - 1 - 2 - 2 is forcing. Fwiw, the bots agree with me on this.

There are many many cases of people agreeing to play convention whatsit and then later finding that they have very different idea of how convention whatsit is played.

Mike Lawrence has a disk on Conventions, and one on 2/1 also, that I got through BBO. The point is not that ML is a bridge god, but rather that there are some concrete suggestions (and if ML is not a god he must be at least somewhere in the hierarchy) . It allows a conversation such as "Let's play convention whatsit and let's do it ML's way" or modifications could be suggested. He doesn't cover everything, bridge has reached a stage where nobody could, but he covers quite a few things.

Back when I played more bridge I and a partner would agree to read the same books and play the suggested conventions the same way. It's a very good idea.