[PhilKing]

 el mister, on 2014-October-14, 02:54, said:

Don't understand that 1eyedjack - pard opens a multi, opp passes and it's reasonably likely that he's 24/25 balanced? That can't be right.

The probability changes with events:

Event 1. Partner opens a multi. The odds are massively in favour of him holding a weak 2 in a major.

Event 2. We look at our hand. The odds of him holding a strong hand increase considerably.

Event 3. RHO passes. The odds rise again.

Now I don't know how much by, but I am guessing they have risen enough to make passing insane - after all, it's not as if pass and 2♥ have greatly differing expected outcomes. But just to show how conditional probabilities can change, imagine:

Event 1 - 1. LHO passed and partner opened 2♦ in second seat. Now, after RHO's pass it would be unreasonable to conclude that partner has anything other than the strong balanced variant.

[mgoetze]

 PhilKing, on 2014-October-14, 05:42, said:

Event 1 - 1. LHO passed and partner opened 2♦ in second seat. Now, after RHO's pass it would be unreasonable to conclude that partner has anything other than the strong balanced variant.

Unless, of course, the opponents are playing an unreasonable defense to Multi.

[PhilKing]

 mgoetze, on 2014-October-14, 17:12, said:

Unless, of course, the opponents are playing an unreasonable defense to Multi.

I guess so - and the conditional probability they play such a defence has gone up hugely.

[jallerton]

 el mister, on 2014-October-11, 04:01, said:

MP club game, fav vuln, pard opens a multi 2♦ in first seat, passed to you. Your hand:

♥xx ♦QTxxxxx ♣Jxxx

Anything to say?

[multi is weak 2M, strong acol 2 in the minors, or massive balanced]

How strong is the 'massive balanced' option?

[Cyberyeti]

 jallerton, on 2014-October-15, 00:41, said:

How strong is the 'massive balanced' option?

OP said 24-25 further up the thread

[helene_t]

 mgoetze, on 2014-October-14, 17:12, said:

Unless, of course, the opponents are playing an unreasonable defense to Multi.

You probably refer to defences like
dbl = take-out on spades
pass = among other things a take-out double on hearts

But isn't it reasonable to pass first with some awkward hands, like hands with both majors?

[Wackojack]

My understanding of the EBU laws re the multi where the following are relavent to the discussion

11G6 The multi 2 ♦ must contain a weak option and one or 2 strong options.
(ii) At least 1 strong option must be of reasoble frequency.
(v) Responder is expected to explore game possibilities if his hand justifies it opposite the stronger option of opener's multi 2♦

If these rules have not been changed recently then the questions that arise are:
What is a reasonable frequency? 24+ balanced = about 1 in 2000 hands. 20+ bal = about 1 in 100 hands.
Then you could argue that if your strong option is bal 20 you could reasonably pass as game is still speculative whereas opposite 24+ you MUST explore further.

I play multi with one partner in EBU land so I would like an answer.

[helene_t]

You must be looking at the old level 3, Jack.

Weak-only is ok at level 4

[PhilKing]

 helene_t, on 2014-October-15, 10:24, said:

You must be looking at the old level 3, Jack.

Weak-only is ok at level 4

But what he is suggesting is that if you do include a strong option, you can't just float it when you don't see partner's lips move.

[Cyberyeti]

 Wackojack, on 2014-October-15, 09:56, said:

My understanding of the EBU laws re the multi where the following are relavent to the discussion

11G6 The multi 2 ♦ must contain a weak option and one or 2 strong options.
(ii) At least 1 strong option must be of reasoble frequency.
(v) Responder is expected to explore game possibilities if his hand justifies it opposite the stronger option of opener's multi 2♦

If these rules have not been changed recently then the questions that arise are:
What is a reasonable frequency? 24+ balanced = about 1 in 2000 hands. 20+ bal = about 1 in 100 hands.
Then you could argue that if your strong option is bal 20 you could reasonably pass as game is still speculative whereas opposite 24+ you MUST explore further.

I play multi with one partner in EBU land so I would like an answer.

Strong 2m is also in there and frequent enough.

I also remember that there is some latitude from a case where somebody passed a multi with a hand with 5 spades and 6 diamonds and about 15 points. That partner had a weak 2 in hearts was reckoned to be so much more likely than a balanced 21-22 in this case that it was fine to pass.

[helene_t]

 PhilKing, on 2014-October-15, 10:28, said:

But what he is suggesting is that if you do include a strong option, you can't just float it when you don't see partner's lips move.

OK, but that just means I can't use UI. If partner's change of suit after my preempt is unlimited I can't pass it when .... is there anything special about multi?

[nige1]

 Wackojack, on 2014-October-15, 09:56, said:

(v) Responder is expected to explore game possibilities if his hand justifies it opposite the stronger option of opener's multi 2♦.
I play multi with one partner in EBU land so I would like an answer

 helene_t, on 2014-October-15, 10:24, said:

You must be looking at the old level 3, Jack.

 PhilKing, on 2014-October-15, 10:28, said:

But what he is suggesting is that if you do include a strong option, you can't just float it when you don't see partner's lips move.

 Cyberyeti, on 2014-October-15, 10:43, said:

I also remember that there is some latitude from a case where somebody passed a multi with a hand with 5 spades and 6 diamonds and about 15 points. That partner had a weak 2 in hearts was reckoned to be so much more likely than a balanced 21-22 in this case that it was fine to pass.

The rules have changed but I remember playing with and against multi, a few years ago, in an EBU pairs event. An opponent earned a top by passing out a multi 2♦ with a good hand but a potential misfit. We studied EBU regulations in force at the time and tried hard to comply with them, ourselves, so we called the director. After consultation, the director ruled that we had no case, explaining that "is expected to" is different from "is obliged to". Laws guru, Grattan Endicott, endorsed this interpretaion on BLML. The incident occasioned some hilarity among the Scottish contingent because the introduction to the (then current) EBU regulations stipulated that players "are expected to" comply with them. It's understandable, however, that local bridge regulations handicap strangers and foreigners. ACBL multi regulations are an extreme example.

[1eyedjack]

What is the point of stipulating "is expected to" in the laws, if there is no sanction for failing to meet that expectation?