Bidding conventions in bridge are agreements between partners that assign unnatural meanings to bids in specific situations. The down side of using conventions is that the natural bids are lost. My favorite convention is called Unusual Over Unusual. What I like about it is that the two bids that it gives up are almost never of any value whatsoever.

U over U is used when the opponents have employed the Unusual No Trump, a Michaels Cue Bid, or any other two-suited bid after your partner has opened one of a suit. For example, if your partner opens 1♦, and RHO overcalls 2NT, he is announcing that he has at least five clubs and five hearts. If RHO had bid 2♦ in the same situation, he would be showing five hearts and five spades. This is a Michaels Cue Bid.

U Over U is designed for these situations. The first thing to do is to map “our suits” to “their suits” using the mnemonic “lower-lower; higher-higher” (or “cheap-cheap”). In the first example above in which RHO used the Unusual No Trump, their suits are clubs and hearts. Ours are diamonds and spades. We map the lower of their suits, clubs, to the lower of our suits, diamonds, and the higher of their suits, hearts, to the higher of our suits, spades.

In the second example above in which RHO used the Michaels Cue bid, their suits are hearts and spades. Ours are clubs and diamonds. We map the lower of their suits, hearts, to the lower of our suits, clubs, and the higher of their suits, spades, to the higher of our suits, diamonds.

The U over U responses are:

• Weak hand without support: pass.
• Weak hand with four-card support: raise partner’s suit using the LAW of total tricks.
• Limit raise or better with support: Bid the suit that is mapped to partner’s suit. This bid is forcing.
• Invitational values or better with no support but five or more pieces in our other suit: bid the opponent’s suit that is mapped to our other (unbid) suit. This bid is forcing.
• Weak hand with at least six pieces in the other (unbid) suit: Bid the suit.
• Double: No support, but a strong enough hand to be able to set at least one of the opponent’s suits.

The biggest advantage of using this approach comes when responder has support. He can distinguish between a weak hand (raise), an invitational hand (cue bid and pass), and a strong hand (cue bid and take additional action). Without the convention his options are much less descriptive. It is possible to assign the limit raise to one or the other cue bids, of course, but if you are willing to go that far, why not just assign both of them?

Many people, including some of my partners, refuse to play this convention because they are afraid that they will forget it. This seems silly to me. Everyone cue bids to show support for regular overcalls. In this case, you have two cue bids available; why not agree to define them? The mnemonic is not that hard.

The worst situation arises when partners have not discussed what the bids after a two-suited overcall mean. In that case, the raise becomes ambiguous. Is partner showing a bust hand with four-card support, a simple raise, or a limit raise? If the opener does not know, he is in a poor position to determine where to place the contract.

You can also use the principles of U over U when the opponents have made a two-suited overcall of 1NT. In this case the biggest advantage may be the ability to alert partner to the possibility of a penalty double. For example, suppose partner opens 1NT showing 15-17 and the RHO bids 2NT showing the minors. If you have three cards or more in each minor and at least five points, you know that the opponents will probably end up playing in three of a minor with at best an eight-card fit and half of the deck or less. If they are vulnerable, you may be looking at a four-digit score on your side of the card.

Of course, if you are playing “stolen bids” (AKA “mirror doubles” or “shadow doubles”), you cannot do this because you have assigned a different meaning to the double.