From: desj@ccr-p.ida.org (David desJardins)
Newsgroups: rec.games.bridge
Subject: Re: A curious question.
Date: 10 Sep 92 00:35:09 GMT
Organization: IDA Center for Communications Research, Princeton

Asya Kamsky <asya@ux5.lbl.gov> writes:
> Too bad, they don't have a choice.  In these cases, each team gets one
> chance to decide what they are playing.  Then you must stick to it.
>
> Same reason the law says you can't change your system during the session.

Is this by itself sufficient?  Obviously it is permissible to play a
system of the form, "If your bid means A, then my bid means B, but if
your bid means X, then my bid means Y."  Otherwise, it wouldn't be
possible to play different defenses against strong and weak notrumps,
for example.  So I think that it is clear that the meaning of a bid can
depend on the meaning of the opponents' *previous* bids.

The question apparently refers to a different kind of conditional
agreement.  Can the meaning of one's bids vary based on the meaning of
the opponents' *subsequent* bids?

On the one hand, there is an obvious problem with this.  Unless some
order is defined in which the sides make their decisions, then circular
situations can result.  It is not at all enough to say that each side
only gets to decide once, because you haven't answered the question of
who has to decide first.

On the other hand, if you ban all bids with meaning based on the
opponents' subsequent agreements, then virtually everyone in the ACBL is
cheating.  For example, I can't believe that most players don't take
into account their opponents' ability to penalize them when they decide
whether and how high to preempt.  I certainly do, and I think that that
is obvious bridge strategy.  (This is precisely what the reference to
Bo-Yin is about; if taking such information into account is illegal,
then one side could be penalized for failing to preempt when they
normally would.)

Another example.  Many pairs have gone into matches against pairs with
strong club relay systems with an explicit plan to interfere extremely
frequently over 1C.  If it is not permissible to play a system which
conditions on the meaning of the opponents' subsequent bids, then such
pairs would not be permitted to play that way if they do not do so
against all strong club systems.

Another example.  I have played against pairs who play negative doubles
after their side opens a strong NT.  Certainly such an agreement is not
completely without merit.  But I believe that the major reason that such
a system works is that the opponents know that you cannot be too
destructive, because most pairs play penalty doubles, and you would get
smashed too often.  They are gaining by playing a system which is
unusual, and which I don't believe is technically superior, but which
works because of the opponents' inability to adapt to it by choosing the
best defense.  (This, BTW, is the supposed reason that the ACBL bans
conventions, is it not?)  (Of course, the main reason that it works is
not that the opponents refrain to adapt because of the rules, but
because they fail to mark it on their cards.  One of my major peeves.)

                                        David desJardins
Newsgroups: rec.games.bridge