[el mister]

I'm just starting with 2/1, learning the system from Thurston's introductory book. It's a very clear treatment ISTM, and as far as the uncontested auction goes I'm doing OK. There is nothing in it, however, on the 2/1 system for contested auctions. I assume there are good authorly reasons for this, but it's got me lost on a few hands given that the opps have a tendency to bid now and again.
Any tips on places to look for a common 2/1 treatments in the competitive auction? First and foremost, can one make a 2/1 game force over an intervening bid, or are systems off? Are Bergen raises still on? Simple things like that would be a good starting place to understand how the system works in these auctions.

On that last point, Thurston introduces Bergen raises early doors, and clearly sees them as intrinsic to the system. If I sit down with your typical 2/1 bridge player on bbo, are they likely to play these raises?

[aguahombre]

Without getting into our personal preferrences: To assist in your search for methods, Responder's new suit bid at the 2-level bid after an overcall of Opener's 1-bid is called a "freebid".

How much strength these freebids show are totally up to you and your partner. Our experience in playing against on-line random pairs is that they have no clue how much strength the freebid should show in the various contexts.

The common categories of freebids are:

"negative"...nonforcing and showing 6-9
"G.F."...ignoring the overcall.
AND,
Probably standard Expert...forcing for one round only.

The Negative Double is used/abused for hands which do not fit a pair's freebid style.

[broze]

aguahombre, on 2013-March-10, 19:48, said:

AND,
Probably standard Expert...forcing for one round only.

What would you define as "forcing for one round only"? I play that the 2/1 bidder cannot pass partner's rebid if the opponents do not enter the auction again. i.e. the 2/1 promises a rebid.

[aguahombre]

broze, on 2013-March-11, 03:37, said:

What would you define as "forcing for one round only"? I play that the 2/1 bidder cannot pass partner's rebid if the opponents do not enter the auction again. i.e. the 2/1 promises a rebid.

Yep..you hit on another thing people disagree upon. In a thread long ago, I contended that a "round" began after the freebid ---thus it guaranteed a rebid; but many others said no.

Pard and I like the G.F. variation, but are in a minority on that.

[fromageGB]

I don't think you can make assumptions, as different people do it different ways. You just agree when you start that a free bid is ... one of the options. GF is very unlikely. The normal strong way will be to X first and bid later, maybe with a cue bid thrown in if absolutely GF. You can't discuss everything before you start, though. When it goes wrong, then you agree what it would mean next time. Without agreement, assume a free bid is forcing you to speak, but if you make a weak sounding response he could pass.

Similarly, you have to agree whether playing Bergen raises. But if they do, they probably do not do it after competition, when the minor bids will be natural.

In my view, if you are learning 2/1 it is MUCH better to have a regular partner to discuss things with, who will play the same way. There are many ways.

[jdeegan]

2/1 gained popularity because it is better for IMP scoring (slam bidding) than ACOL or SAYC, et. al. Originally, the adaptation to competitive auctions was to continue to play the old system, eg. SAYC. This made sense because relatively few competitive auctions end up in slam, and you can handle most of these with the older methods.

In the ensuing years different innovations have been tried by various pairs such as light two level responses (negative free bids) or various riffs on the negative double. My advice for newer players is to use the original approach - 1 level bids just ignore the interference (6+HCP), and 2 level bids advertise 10+ HCP and promise one more bid.