Smolen
By Mike Smole

As explained in John Blubaugh's article in the May 1995 ACBL Bulletin the Smolen convention was devised by the late Mike Smolen of Los Angeles to allow the notrump bidder to become declarer when responder uses Stayman with 54 or 64 distribution in the majors.

When partner opens 1N, you bid Stayman, and partner then responds 2D (no four card major) these subsequent bids have the following meaning, and both are game forcing. You jump in the 4 card major to show 5 in the other.

2H         invitational with 5 spades, 4 hearts
2S         invitational with 4 spades, 5 hearts
3H         Five spades and  four hearts
3S         Five hearts and four spades

After your jump, partner can bid 3NT to deny three-card support for your long suit, then if you have 6-4 distribution you can retransfer, just as in Advanced Jacoby.

This keeps the strong hand concealed, unless, of course, you are using 8-10 HCP one notrump openers!