The jump overcall is defined as when one side makes an opening bid and the other side bids a new suit at one level higher than necessary. For instance, North opens 1C and East bids 2H. If East had merely bid 1H, that would show a five-card heart suit and about 8-15 HCP. But the jump overcall is used to mean something different.
In Standard American, a jump overcall is usually played as being “weak”, the equivalent of opening a weak two. In the case above, you might overcall 1C with 2H if you had something like S xxx H KQT9xx D Qx C Jx. A six-card suit precisely and somewhere between 6-12 HCP, depending upon vulnerability and nerve. (If you overcall 3H, you’re showing a hand that would have opened a pre-emptive three-bid had it been first to speak; seven heart cards and about 7 HCP.)
This, of course, is primarily meant as obstructive. It’s not likely that you can bid to a game after the opponents have opened of their own free will; occasionally, though, you can bid a thin game if you have lots of trumps and well-fitting hands. But what you’re really most interested in doing is (a) indicating a good lead to partner, and (b) forcing the bidding to a higher level before the opponents have had a chance to exchange information comfortably.
Those are both good things to do, and the weak jump overcall is useful in that respect. You might find that you seem to be giving away a lot of 50s and 100s and the occasional 200 … that’s what happens when you bid pre-emptively. It’s always worth looking back at your scores to see if your WJOs are paying off or costing you more than you think.
I don’t say it’s likely that WJOs are costing you matchpoints. It depends on your bidding style, the strengths and weaknesses of your usual opponents at the Tuesday night game … whether you play your cards better than others. But as I said, your hand records will tell you your matchpoint gains and losses and you’ll be able to decide if you want to continue playing WJOs.
That’s because, as you may have gathered from the title of this piece, there is another way to play jump overcalls that actually works, and more to the point, it fits well into your existing bidding system and solves a problem.
In order to explain — let’s give you a hand like S AJxxx H x D Qx C AKxxx and you are second to speak at equal vulnerability. “Great!” you think. “If she opens 1H I can bid 2H Michaels, showing spades and a minor.” But, in the way of such things, your RHO comes up with an opening bid of 1D. Of course, it would be best to show both suits at the same time; if you merely bid the spades, you’ll have a hard time convincing partner you have five clubs too. You have another way of showing two-suiters in your arsenal, but over 1D, the Unusual 2NT usually shows the two lowest unbid suits — hearts and clubs, in this case. So your methods for showing two-suiters have a hole in them. You’re pretty much stuck with overcalling 1S and trying to catch up later if you can.
However, the clever Italians — I believe this is from the famous Blue Team and Benito Garozzo, one of the greatest players of all time — came up with a way of describing ANY two suiter with a single bid. They kept Michaels and the Unusual NT, and added Roman overcalls. (So named because they lived in Rome!) This is how they work.
A Roman jump overcall shows the suit you bid, and the unbid suit above it, 5-5 or better.
So in the above example, after RHO opens 1D and you’re 5-5 in the black suits, you can bid 2S. That shows spades, the suit you bid, and clubs, the unbid suit above it. It doesn’t matter which two-suiter you have, if you play Michaels, UNT and Roman overcalls, you can show any two-suiter.
Note the “unbid” suit above idea. That lets you show, say, 5-5 in spades and diamonds after RHO opens 1C. 2S shows spades — the next suit above is clubs, but that’s been bid, so you ignore clubs and show diamonds.
To test it another way: RHO opens 1H. If you bid 2H Michaels, you show spades and a minor (in this case probably diamonds, because you have another way to show clubs). If you bid 2NT Unusual, you show clubs and diamonds. And if you bid 2S Roman, you show spades and clubs.
How many points should you be showing? That’s up to you. My own thinking is that two five-card suits are a considerable and unusual asset that is very valuable in the play, and is worth a lot more than whatever your HCP counts up to. I confess that, depending on the vulnerability, the precise hand, some timid opponents, and my particular degree of aggression on any particular night, I might do it with zero HCP or a very poor point count (then it becomes pre-emptive). In a situation like that, the minute I get a preference from partner for one of my suits, I drop him in it. But if I have more, I bid more. If I hear a preference from partner and bid again, I should be showing about an opening bid.
As you can see, when you have a situation that calls for this precise bid, it comes in very, very handy; you’ll be bidding in a way that few others in your field have the tools to do. You have to balance that against the frequency of how often the WJO comes up, and what results you’re getting from using it. You may find that Roman overcalls don’t come up all that often and you’ve just traded a common bid for a rare one; that’s a common complaint. But if you’re what I like to call a “busy bidder”, someone who likes to get in there and show distribution and suggest leads and stir things up a bit, Roman overcalls may just be useful to you. Perhaps you should take them for a test drive some night and see what you think. They are, not surprisingly, alertable.
Oh, and what do you do when you have agreed to play Roman jump overcalls and you pick up a hand that qualifies as a weak jump overcall? Simple — overcall at the cheapest level and if you can, repeat the overcall. That guarantees six. Of course, you’ll have to use your judgment as to whether you have the points to bid twice. At least you will have interfered and gotten partner off to the best lead.