Source: Bridgewinners by Steve Weinstein and Dan Wolkowitz Feb. 8, 2012
Mixed Raises Part 1: How to Bid and Defend Against Them
The Major-Suit Mixed Raise Without Interference
Bergen Raises have now been around for over thirty years, but when watching top experts in action it seems that fewer and fewer of them play Bergen Raises as originally written. In fact, many have replaced the preemptive raise, Bergen’s hallmark, with the mixed raise.
What is a mixed raise? A mixed raise is another name for a 4-card constructive raise (The 3
bid in Bergen’s system). The idea behind it is twofold. First, it separates hands that would normally raise to 2M by their trump length: three vs. four trumps. Often the extra trump provides the necessary ruffing potential and trump control to make game a reasonable prospect. The higher bid also raises the auction directly to the 3-level, preempting more of the opponents’ possible actions while still providing enough juice to often make nine tricks. Mixed raises tend to be about 6-9 HCP when non-vulnerable and 7+-9 HCP vulnerable. The reason for this is that opener will be more aggressive at bidding games when vulnerable at IMPs so it’s better not to make him guess. There is also the risk of voluntarily going -200 when vulnerable for a zero at pairs.
Which of these hands qualifies as a mixed raise after partner opens 1
Vul? Non-Vul?
Answers:
1) Yes, because of the prime cards but a minimum when vulnerable.
2) Only if you are non-vulnerable.
3) Yes, but on the maximum side.
4) No, it is a limit raise – all the high cards are working in long suits.
5) A mixed raise non-vulnerable despite the soft values. Worth a mixed raise vulnerable if the 
Qx were the Kx.
Many 4333 hands are less than ideal for mixed raises. Some can be downgraded to simple raises despite having the right point count and trumps. Without ruffing values the extra trumps only help with control. Although the opponents might be able to make something, pushing the auction to the 3-level with one of these hands increases the chance of turning a plus into a minus or ‘stealing’ the contract for -200.
Playing 1M-3M as a mixed raise, there must be another bid to show a traditional limit raise. One possible treatment is to play 2NT as a limit raise or better (Jacoby Plus). Another possibility is to use 3. Even if the limit raise is artificial, the risk from it being doubled is less than if it were a mixed raise since your side has the balance of power.
They Overcall
Preemptive raises are more useful when the opponents are already in the auction. When you hold a very weak hand and both partner and RHO have shown good hands, there’s a good chance that your side is on the short end of HCP. However, mixed raises are also useful in competition. When partner opens the bidding and RHO interferes, a mixed raise conveys both trump length and strength to partner. This could be crucial when the opponents also have a fit. If the auction is at the 5-level by the time your partner makes his next call, at least you have conveyed the rough offensive and defensive potential of your hand. Therefore, it’s more reasonable to have a way to show both raises once the opponents are in the auction than when you’re in an entirely constructive situation. The preemptive raise should be natural, to take up as much bidding room as possible when the opponents are more likely to have strength, so the mixed raise has to move. 3M-1 is a good spot because it uses up the maximum amount of remaining space. Exception: If 3M-1 happens to be the cue-bid (i.e., 1 (2
) 3) then the cue-bid is still limit+, and 3M is mixed (no preemptive raise). If we are favorable, then 3M is wide-ranging (preemptive to mixed).
What would you bid with these hands after the auction 1-(2)-? (3 is now a mixed raise and 3 is preemptive)
Answers:
1) 3. Three small diamonds plus the risk of 3 being doubled. Mixed non-vulnerable if the Q were the K.
2) 3. The extra shape and the working K make this a mixed raise even when vulnerable.
3) 3. A typical mixed raise.
4) 3 if non-vulnerable, 3 if vulnerable. xxxx is much better than xxx and the singleton club gives this hand much more playing strength than a non-vulnerable 3 would have.
5) 2. A very low offense-to-defense ratio.
6) 3. This hand is very strong behind a diamond overcaller.
Once the opponents are in the auction, your hand evaluation should change considerably. You can upgrade kings or aces with connected jacks and downgrade slower holdings such as QJ. This is the most critical moment for a mixed raise because if you can accurately describe your hand’s character with your first bid, that may be all your partner needs to make the right decision down the road.
They Double
When the opponents make a takeout double of 1M, we suggest the same treatment as when they overcall: use (3M-1) as the mixed raise and 3M as the preemptive raise. The only difference is with regard to hand evaluation. Similar to an overcaller, the doubler rates to have strength in the other suits, so AJx KJx AQx and other side-suit tenaces are far more valuable than in a constructive auction. You might also choose to play 3NT in this position as a raise to 4M with some defense to prepare for the 5-level.
Defending Against Mixed Raises
Mixed raises are important even if you choose not to employ one in your own system. Understanding their strengths and weaknesses will help you defend against them.
When the opponents bid 3M as a mixed raise, you’re in a bad position. They have a good chance of making this contract if you pass, and if they have a game they’ll likely know to bid it. If you enter the auction and you’re wrong, you may end up paying a price for your folly.
On the other hand, if the opponents bid an artificial suit as a mixed raise, your options open up considerably. For example, in the auction (1M)-p-(3)-?, we suggest playing double by an unpassed hand as takeout of their major (lead directional by a passed hand). The mixed raise tells you that the opponents probably have at least half the deck, but they do not have to have more and they might have less. They also possess a 9-card fit, which means that your side has at least one eight-card fit. You often have a reason to compete for the partscore and will even have the occasional game. The need to compete is even stronger when they have opened 1, as you want to avoid being blown out of spades. Doubling for lead-direction only works when you really need a club lead or you hit the jackpot and find partner with clubs. Against that, you lose whenever you needed to compete in hearts or diamonds. Another plus for you is that the opponents are unlikely to catch you when your partner is broke. It is rare for a side with nine trumps in a major to want to play in three-of-a-minor doubled and it is even rarer to figure out when that time is. When opener has a good hand, he will generally just bid a game. You might reveal some of your cards to him, but you likely won’t be handing him a number.
After you make a takeout double or overcall and the opponents bid 3M-1 as a mixed raise, we suggest you treat this the same way as a jump raise in their initial suit and play the double as responsive. While in special cases other agreements might be useful, the infrequency of this situation suggests that you choose an easy-to-remember solution.
Tune in for part 2, covering mixed raises in minor-suit auctions, and after partner’s overcall.