The system of Bergen raises is based on the idea that you want to compete to the 3-level with nine trumps. Bergen raises are used in conjunction with the forcing NT, so that you have bids to describe all types of raise hands after partner opens one of a major.
Here are the Reverse Bergen bids:
- Raise to two shows 6-9 points and exactly three trumps.
- Raise to three shows 0-6 points and exactly four trumps.
- Raise to four shows less than a limit raise and five+ trumps.
- Jump to 3♦ shows 7-9 points and exactly four trumps.
- Jump to 3♣ shows 10-12 points and at least four trumps.
- Bid 1NT and follow with a jump in partner's major to show 10-12 points and three trumps.
- With three trumps and an opening hand, bid a new suit.
- With four trumps and an opening hand, bid Jacoby 2NT, a new suit or splinter
All Bergen raises are alertable.