[dickiegera]

Playing Bergen raises

Are they on after interference?

1. After Overcall
2. After Double

We have played on after a double however we have no agreement over an overcall.

Thank you

[gordontd]

It depends on agreement, but I wouldn't. I'd prefer to play fit jumps.

[manudude03]

I don't mind playing bergen raises over a double. After an overcall, it is playable over a 1 level overcall, but unplayable over 2 level interference imo. Ultimately, it is down to partnership agreement.

[blackshoe]

Bergen himself invented BROMAD to deal with 1M-(X). Workable, but I prefer Cappelletti (no, not the Cappelletti that's used over opponents' 1NT opening, a different one), probably because I learned it first and because I like transfers. I think Bergen recommends Bergen raises be off after an overcall. In any case, if you don't have an agreement, you need to make one.

[fromageGB]

Need partnership agreement for all levels and types of interference. My preference after a double :
system on in entirety.

My preference after natural simple or single jump overcall is :
X and up to suit below partner's = transfer to next step (eg 1♥ (1♠) X = transfer to NT, while 1NT = transfer to clubs)
.. with a transfer to partner's suit being "full strength", ie transfer to 2M is 3 card 7-10 hcp, and ..
immediate support = weaker
new suit above next level of partner's = natural, forcing unless passed
2NT = 3 card support 11+ hcp
opponent's suit = 4+ card support 9+ hcp
raise to 3+level = 4+card support, up to 8hcp
jump (or double jump) new suit = fit jump = 5 card suit with a raise hand good enough for that level.

So applying this to your Bergen bids, 1♥ (1♠) 3♣ = fit jump, but 1♠ (2♥) 3♣ is forcing natural suit.
Your Bergen hands are likely to be 1♥ (1♠) 2♠ (or 3♥ if you bid them that weak).