I recently proposed that the sequence 1NT - 2♣ ; 2M - 3m primarily ask if opener has a stopper in the bid suit, but the idea generated little interest. Let me elaborate on why I think it's a very effective way to deal with several different hand-types while costing almost nothing compared with standard methods.
First, however, note that the proposed approach requires the following agreements:
1) Responder may not bid Stayman without at least one four-card major. (Find another way to invite in notrump!)
2) With both four-card majors, opener responds to Stayman by bidding two notrump (minimum) or three clubs (extras). If a partnership chooses to play garbage Stayman, it will sometimes play in three of a major, but with the consolation of usually finding two eight-card or longer major-suit fits.
3) If opener doesn’t have a four-card major, there’s a way to play this structure, but it's not pretty. Check out the footnote below* if interested, else revert to natural bidding.
After an auction begins 1NT - 2♣ ; 2M, responder’s three of a minor is initially treated as a try for three notrump with a singleton or two small cards in the bid suit (though as shown in the examples below, responder may also have length there). Opener bids 3NT with the ace, king-doubleton, queen-third or better in responder's minor. With less, he rebids a five-card major or a four-card major strong enough to play in a four-three fit. With neither, opener bids an artificial three-of-the-unbid-major.
This approach has several possible applications as illustrated below in sequences beginning 1NT - 2♣ ; 2♠ - 3♦. It allows the partnership:
1) to find a five-three or strong four-three major-suit fit. Consider AKJx Ax Jxx Qx opposite Qxx Kxxx xx AKxx. Responder bids 4♠ over opener's 3♠.
2) to bid a good slam when opener has no wasted values in responder's short suit. Consider AKTx Axx Jxx QJx opposite QJx Kxxx x AKxxx. Responder bids a dramatic 6♠ over opener's 3♠.
3) to learn if opener holds a fitting honor so that the suit is likely to run. Consider AJxx Kx Kxx KJxx opposite xx Axxx AQJxxx x: Partnerships need to decide whether 4m is forcing if opener doesn't bid 3NT.
4) to look for a minor-suit slam. Consider Axxx Kx KQxx Axx opposite K Axxx AJxxx Kxx. Over 3NT, responder's 4♦ shows 5+ diamonds, and opener cuebids 4♥ with interest in a diamond slam. (He could have bid 4NT to sign off.) Then responder takes over with RKC and it’s not hard to reach the grand.
If your partnership doesn’t have a better way to handle three of minor and its continuations, you might want to give this approach a try.
* Over one notrump - 2♣ - 2♦, responder bids 3♣ as a relay to 3♦. Responder then bids 3♥/♠/NT (showing clubs) to name the suit in which he lacks a stopper. Responder’s 3♦ over 2♦ follows the usual approach with three of either major showing a concentration of strength without a high diamond honor.
