[awm]

This time suppose opponents bid either:

1♠ - P - 2♠

Or:

1♠ - P - 1NT(forcing)

You have a borderline hand with a bunch of diamonds. Would you bid more aggressively in the first auction or the second? Or are there hands you'd bid in either case and pass in the other? Obviously the opponents fit in the first auction might give you some protection, but you're also a full level higher.

Again assume that opponents play fairly standard methods. The 2♠ bid is not necessarily a "constructive" raise. The 1NT forcing could conceal a 3-card limit raise or a weak raise.

[mike777]

over 2S Obar.
more aggressive auction one.

[benlessard]

Its take more strenght & more courage to overcall at the 3 level when the opps X will be penalty. Then to overcall at the 2 level where you will rarely be doubled. Of course you should be inclined to be agressive when opps have a fit, but there is just no comparaison between the 2.

you have to remember that in sequence 1 you either have to hope partner can raise you back to 4D or that opps will go down in 3S or that they will let you play 3D and you will make it. Pushing them in a 3S that they will make give you no profit.

In seq2 however the opps are less likely to compete at 3S so buying the contract at 3D is a better possibility also you bury their clubs fit.

[Apollo81]

The first auction. It is called pre balancing for a reason.

[dake50]

Are oppts about to misjudge their tricks or their fit? 3S over 3D, even 4S over 4D, or Dbl will be wrong?

I think not, so 3D over 2S has little upside. I think 2D even with a D-preempt is more likely to steer them wrong in the F 1NT auction.

Besides what evidence do I have that PRE-balancing is needed? Partner hears this auction too.

[foo]

It is always safer to compete when They are known to have a fit rather than when the hand is or might be a misfit.

In addition, there is no need to be hyper-aggressive vs a Forcing 1N response. Since Opener will not pass 1N, you don't have to commit yourself quite as quickly with borderline hands.

Finally, keep all of
a= the vulnerability ratio
b= the level you have to compete at
c= where your values are placed compared to theirs
d= the conditions of contest
in mind when you decide what to do.

...and in general, the weaker Their bid, the sounder your bid should be.

[brianshark]

When they have a fit, we have a fit.

[jtfanclub]

Ummm...no expert here, but I'd feel very silly if I bid 3♦ and it turned out our fit was clubs. So there are a few hands where I'd pass OBAR but not pass 1NT, depending upon my length in the 'skipped' suits.