Bidding and conventions
Bergen raises
Partner opens 1♠. You hold four spades and 5 points. Bergen raises say bid 3♠ — immediately, on a hand most players would raise to two, and the reason is a piece of arithmetic about trump length rather than optimism about your cards.
Why the weak hand jumps to three
The Law of Total Tricks holds that it is safe to compete to the level of your combined trump length: eight trumps between the two hands means the two level, nine means the three level, ten means four.
Partner has promised five. You hold four. That is nine, and the three level is where the hand belongs whether you hold 4 points or 10.
If the contract fails, the opponents almost certainly had a contract of their own that was making.
4 points. A raise to 2♠ invites the opponents in at the two level; 3♠ makes them start at four.
The preemptive raise is the part of Bergen that wins the most, and it wins it by taking bidding room away from opponents who almost certainly hold the balance of strength.
What each bid does
The full structure, once four-card support is shown by a Bergen bid and three-card support by everything else:
- Two of the major — 6–10 points, exactly three trumps.
- 3♣ — 7–10, four trumps. Opener passes with a minimum or bids game.
- 3♦ — 10–12, four trumps. A genuine invitation.
- Three of the major — 0–6, four trumps. Opener bids game or passes; it is not an invitation and should not be treated as one.
- 2NT — Jacoby 2NT: 13+ with four trumps, forcing to game.
- A double jump in a new suit — a splinter: game values, four trumps, shortage there.
| West | North | East | South |
|---|---|---|---|
| 1♠ | |||
| Pass | 3♦ | Pass | 4♠ |
| Pass | Pass | Pass |
What the partnership gains is that trump length and strength become separate messages.
Standard methods bundle them: a raise to 2♠ might be three trumps or four, and opener guesses which on every competitive decision that follows.
Reverse Bergen
Many partnerships swap the two artificial bids: 3♣ becomes the limit raise and 3♦ the constructive one.
The argument: the limit raise is the hand where the auction continues, so it should take the least room — leaving 3♦ free for opener to ask questions below three of the major.
It is a small gain and a complete reversal, so the two versions cannot be mixed. Write down which one you play.
When it applies, and when it does not
- Only over a major. After a minor opening, 3♣ and 3♦ keep their natural meanings.
- Only by an unpassed hand, in most partnerships. A passed hand uses Drury instead, which solves a different problem in the same auction.
- Only without interference. If the opponents overcall, normal competitive methods apply.
- Four trumps, not three. The whole structure rests on the trump count being exact, and a Bergen raise on three cards makes every later decision wrong.
What it costs, including the part usually left out
You give up the natural jump shift into 3♣ and 3♦, which is a genuine loss but a small one: a hand with a strong minor and no support has other routes.
The larger cost is the one most write-ups skip. Every Bergen bid announces your exact trump length to the defenders before the opening lead.
They know the suit breaks 5-4 — on the hands where you stopped in a partscore as well as the ones where you reached game. Standard methods leave that ambiguous, and ambiguity has defensive value.
This is why strong partnerships are split on Bergen rather than universally in favour. The preemptive raise is worth a lot; the two artificial bids buy accuracy in exchange for information, and reasonable players disagree about the rate.
If you remember three things
- Four trumps is the entry condition. Three trumps means an ordinary raise.
- Nine trumps belong at the three level whatever your point count.
- Agree Bergen or Reverse Bergen in writing. They are exact opposites.