[Free]

My partner came with the idea of playing Jammer 2♦ opening in 1st seat NV. There are several versions of this opening, but he suggested to play the long ♠ version (so it's not BSC).

2♦ = weak, 4-5♠ with 3-5 cards in 2 other suits (and 0-2 in the 4th suit).

This only encompasses 4432, 5431, 4441 and 5440 distributions (not 5332). This obviously is very agressive, very frequent, seems like a lot of fun, but I just wonder if it's any good.

I've found the article partner referred to, but it doesn't say much about responses, continuations and constructive bidding: http://www.bridgebuff.com/jammer.html

Does anyone have any experience with this type of opening?

[awm]

I've played quite a bit against a stronger version of this opening, and the results for the opening side are absolutely horrendous. Some of the problems which seem to crop up:

(1) Some of the fits described are at the three-level; while a seven-card fit at the two-level is okay and an eight-card fit is quite good, the identical fits at the three-level fare substantially worse.
(2) There are correlations between responder's length and opener's shortage which may not have been taken into account properly by the frequency calculations.
(3) You often generate a fairly long scramble auction when you have fairly bad hands, which gives the opponents ample opportunities to intervene/double you or at least figure out shape prior to the lead.
(4) Opponents can avoid some of the problems defending anchorless preempts by using spades as a "cuebid" in various auctions.
(5) Looking for game is quite hard; there are many responder hands with hearts (for example) which make game when opener also has hearts but need to get out cheaply when opener is short hearts. There is a related issue that 5314 has ridiculously better playing strength for a spade contract than 4423 with the same high cards.

Problem five is likely reduced somewhat by the weaker range, but the other problems potentially get even worse than they would be otherwise. I'm not much of a believer in this type of bid. It seems like playing a 2♦ opening which shows 4+♦ and 4+♥ (for example) might be substantially more effective because it can be passed and partner knows both suits.

[JmBrPotter]

I'd second Adam's comments and offer the following additional alternatives if they fit your system and jurisdiction:

- 2♦ as a weak two bid (old fashioned, easy, and reasonably effective)
- 2♦ as Multi (edgier, restricted some places, and playable)

I recommend against the Flannery 2♦. Just open 1♥, and if Partner cannot bid 1♠, suppress your spades and see if the opponents will be kind enough to bid them for you. Because Partner and I rebid in a canapé style, we open Flannery hands 1♠ and rebid 2♥.

[dake50]

1st. Jammer 2D with hearts --intending to get above their 1S opener seems to fit weak-obstruct intent better. Spades just bids spades at appropriate level.
2nd. Have 2NT as similar with some other non-spades weak-obstruct hands. The two could partition the weak-obstruct quite well.
3rd. Disallow much in the other Major --oM:Jx is max expected.
Then, partner may often make good guesses (with little fear -800) to preempt this auction.

[Siegmund]

I am never quite sure if "Jammer" is intended to be English or German when I hear of this convention....

I will second the suggestion to use hearts as the anchor rather than spades. But still, it's going to be quite a bit less effective than conventions where opener promises a bit more shape and you can scramble more confidently. I would not be convinced that there's a reason to play it, other than experimentation and generally sowing chaos.

[gnasher]

If you play it, I think you should make it very weak, with an upper limit of about 6, so that it's rare that you'll need to investigate game.

Also, you should be very cautious about preempting opposite this. A 4-4 fit without much high-card strength doesn't usually produce many tricks. With this sort of method, it's usually right to assume that your system has already done its job.