The following appears in the book authored by Mr. Larry Cohen in his publication entitled: To Bid or Not to Bid - The Law of Total Tricks beginning with page 118-119. The content of this web page is an excerpt from this book and posted to the Internet with the permission of the author and whose personal website is online.
Contribution Information
Most people play Unusual 2NT to show the two lowest unbid suits. Its normal application is a jump over the opponent's opening bid.
We also play Unusual 2NT after they've bid and raised. However, it shows any two suits - not necessarily the two lowest. What if the bidding goes 1
- P - 2 and you hold
You'd hate to guess which suit to "balance" with. If you make a takeout double, you know that your dumb ol' partner will bid three diamonds.
So, we bid two notrump saying: "Partner, I have two suits - bid accordingly." If partner has 4-1-5-3 shape he'll start out with three clubs in response, knowing that, if you have red suits, you'll convert to three diamonds. If clubs is one of your suits you'll pass. Yes, if you have clubs and diamonds you'd be in your eight-card fit instead of your ten-card fit - but the objective of getting into these auctions is simply to find any fit.
Playing two notrump equals any two suits, and responding cautiously, we are able to sneak into the auction safely, confident that we'll be able to land in a playable trump suit.
If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.