In Duplicate some of the least productive boards occur when opener and responder have no competition. Most of the bids are well known, often used and over the years have become well defined. Constructive bidding can also occur between Overcaller and Advancer, but bad results frequently prevail because the bidding sequences are less familiar. The problem usually starts with Overcaller and ends with Advancer.
A direct overcall has a multitude of purposes, but the principle purpose should be to engage in constructive bidding when the hand is "ours." You don’t have to nag me about the defensive benefits of getting into the auction, but it’s putting the cart before the horse if your overcalls are so bad that constructive bidding cannot occur. Simple overcalls already have a mega wide range (8-18 hpcs). You might overcall with (i) xxx, KQTxx, Kxx, xx, and also this (ii) Ax, AQTxx, KQx, Kxx. Through out this post I am going to refer to Losing Trick Count (LTC) as I think it is a better measure of strength and playability when partners have an 8 card fit. If you don’t know this hand valuation system, you are doing yourself a disservice. In the March 2007 blog archive you will find a two part post on LTC,
Here is Tommy’s thought #1 (fortunately most experts agree with me) : Do not overcall if you have a hand that has more than 8 LTC! Pass up hands like xx, KQxxx, xxx, xxx. Go back, read it again and tell me how partner is ever supposed to differentiate between this overcall and example (ii) above. Sensible communication has just been thrown out the window and this hand can only have a good result if everybody ignores you.
You are probably looking at example (ii) and saying why not double first and then bid. Here is Tommy’s thought #2: Much unnecessary damage is created by doubling and then bidding when a simple overcall will not have any risk of losing game going hands. If partner has any 3 card support and as much as 5 hcps (9 LTC) he is going to take a bid. If he has a bust or even as much as 5 hcps without a fit, how are you going to feel about bidding your heart suit at the 3 level. The key is don’t be afraid to make a simple overcall with a really good hand and save the double and bid treatment for the monster hands with no more than 4 LTC.
Moving to Advancer’s side, the key to good constructive bidding is the “cue bid” which describes an invitational hand or better. Almost always this hand will have 3+ card support and will have no more than 8 losing tricks. The cue bid by Advancer asks Overcaller a simple question: Do you have opening hand values? If you rebid your suit it says “NO”. If you make any other bid it says “Yes.” A useful understanding is that any suit bid other than the overcalled suit is a “help suit” game try, since a presumed fit has been announced by the cue bid.
Now we can see the importance of maintaining discipline with overcalls and advances. If Overcaller's answer is "Yes", we know he probably has no more than 7 losing tricks. Now, if Advancer has extras and no more than 7 losing tricks in his hand, the two hands have 14 or fewer total losing tricks and taking 10 tricks in our 8 card suit is most likely. If Advancer had a minimum cue bid, 8 losing tricks, he can bid overcaller’s suit at the 3 level and this is “Stop.”
The use of the cue bid is effective because all other bids at the 2 level are non-forcing and all raises are pre-emptive (Law of Total Tricks). Since cue bids strongly imply at least 3+ card support we need bids to deal with very good hands with no support. Cue bidding when you have no fit can lead to many problems. Consider other bids such as 1NT (which does not require a minor suit stopper). If your RHO takes a call over the overcall, a responsive double can work well to show the hand. If you cue bid without support, it should show a good 6 bagger and no more than 6 losing tricks. Without a fit, you need that type of power.
Just so you don’t go away empty handed, here are a couple of ideas you may not thought about. There is not much use for the jump shift by Advancer so a common agreement among better players is that a jump shift by Advancer shows a splinter bid, 4 card support, shortness in the bid suit and about 7 LTC. Another useful bid is the “jump cue bid” to show 4 card support without shortness. Now we can differentiate between a single cue bid (3 card support), the jump shift (showing the "splinter") and the jump cue bid (4 card support and no shortness).
I hope you enjoyed this review. Good basics will get you more results than one more convention.I would like to acknowledge the valuable insights that were provided to me about overcalls and other good bridge by Alan DeSerpa's excellent book, The Principles of Logical Bidding.