On 2013-01-26 5:52 AM, Bruce Evans wrote:
> I think it is illegal to have agreements to switch to a system that
> can better handle previous irregulaties by your side.
That's true, if at all, only in particular jurisdictions that have a
specific rule. There's nothing to that effect in the worldwide Laws.
> Changing 2C to natural would be such an agreement
If this is the first time the situation has come up in your partnership,
it is wildly unlikely you have an agreement. So no problem at that
moment. Everyone is allowed to know the effect of the Laws and apply
bridge logic to the result.
Where there _might_ be a problem _in the ACBL_ is the second or later
time this situation arises. Then you might possibly be deemed to have
an agreement contrary to ACBL regulations. I don't think that's likely
in any realistic scenario, but if somehow it applies, you could either
dissolve your partnership or accept a big (though I think unspecified by
the ACBL) penalty every time the situation arises. As I say, this whole
thing seems far-fetched in real life.
> A related question is whether it is AI for partner to know that his
> forced pass is AI to both him and you.
Answered elsewhere: yes.
> But pysches of 2C may be illegal.
Answered elsewhere: bidding 2C to show a club suit when partner must
pass has nothing to do with psyching.
> Consider multi 2D. You hold a weak 2 in diamonds, say xxx xx KQJxxx
> xx. Can you open 2D natural?
[if partner is barred, I presume]
Sure, why not? Of course you might also bid 2D with a rather stronger
hand, though not one so strong that 3NT is a logical alternative.
> I think it is legal for the opponents to have an agreement to better
> handle your irregularity.
In general yes, though ACBL forbids you to "vary" your agreements. Here
the situation would be a natural but wide-range 2D opening. If you have
an agreement over that, the ACBL says you have to stick with it. Other
jurisdictions may have no such rule.
> - what is AI in further rounds of bidding?
> - what is AI in defence?
Same things that were AI all along.
This is really not complicated in principle. The only hard part is
judging logical alternatives in specific cases, but that's no different
than any other UI problem.