[Jinksy]

If we play 3N as showing a good preempt in a major, is there an expert standard meaning for X for the following:

Opps overcall 4m
Opps overcall 4M
Opps X 3N

In the last case, what about pass and XX? And assuming that allows playing in 3NX(X), what about Xes if they run?

[steve2005]

Double of 4 bids should be penalty. You know partners hand if you want to play in opener's major you can or even make a slam try. You don't need double to find a suit possibly at 5-level.
last question depends on what double means. I think standard is either strong balanced or 3-suited takeout. I don't see sense in playing redouble as anything but interest in penalty for same reason as first two questions but I'm sure there are other possibilities.

[Jinksy]

steve2005, on 2017-August-05, 10:28, said:

You know partners hand

Do I? We're still figuring out the boundaries for 3N and 4M bids, but 3N seems very unlikely to include 'solid suit'. Thus with Qxx x Axxx AKxxx, if it goes 3N (4♦) to me, it's obviously better odds that P has hearts, but there's no reason in principle why his suit couldn't be spades.

[jallerton]

Jinksy, on 2017-August-05, 04:13, said:

If we play 3N as showing a good preempt in a major, is there an expert standard meaning for X for the following:

Opps overcall 4m
Opps overcall 4M
Opps X 3N

In the last case, what about pass and XX? And assuming that allows playing in 3NX(X), what about Xes if they run?

There probably isn't an expert standard, in the sense that it's not a particularly common auction, but without discussion, most would assume that double is penalties. If they overcall 4m/4♥, then Responder's pass should be placed as forcing. This gives plenty of room to sort out the hand types. If you want to get really cute, you can play 3NT (4m/♥)-Pass as a puppet to double [either a penalty double or something else] and double as suggesting, but not insisting on, a penalty.

If they double 3NT (less likely than an overcall) then it's easiest in practice just to play "system on". You can attach meanings to pass and redouble if you like, but this is not the most important sequence to worry about!