Main Structure 7G71 by Richard Pavlicek
In the late 1970s a concept known as unusual over unusual was developed (not sure by whom) to cope with an opponents unusual 2 NT overcall. While reasonable, its specific application to one type of two-suited overcall was shortsighted. Therefore, I generalized it for all two-suited overcalls and added some additional agreements. Basically, the cheapest bid in an enemy shown suit is a raise of openers suit (see details for more).
The name also had to be changed (e.g., unusual over unusual sounds stupid if the enemy bid is Michaels) so invisible cue-bids were born. (This was introduced in 1981 in Modern Bridge Conventions, a book I co-authored with Bill Root.) Alas, the name didnt catch on.
After a Michaels cue-bid, unusual 2 NT, Roman jump overcall, or any other bid that shows a two-suited hand, the following structure called invisible cue-bids applies:
3 NT jump
3 NT nonjump
Any jump cue*
10+; creates forcing auction
6-9; 6+ (good 5) cards; NF
9-11; natural with fit; I
12-14; natural with fit; NF
9-14; natural with fit; NF
10+; raise of suit opened
10+ HCP; 5+ cards in the 4th suit; F
13+; splinter raise; GF
*A bid is a cue-bid only if the suit was specifically shown. The higher cue is available only when two specific suits were shown.
1. After the higher cue, if opener rebids in notrump or his original suit, this confirms a minimum and is nonforcing. A raise of responders indicated suit is forcing below game.
2. After doubling, if responder next bids a new suit or a suit implied by the enemy, it is natural and forcing below game.
3. If responder passes over the two-suited overcall and later bids a suit implied by the enemy, it is natural and nonforcing.
© 2013 Richard Pavlicek