The popular Inverted Minors convention switches (or "inverts") the standard meaning of the strength of minor-suit raises.
In "Standard," a raise from 1 to 2 (or 1 to 2) shows 6-9, while a raise to 3-of-the-minor shows 10-12 (limit).
If playing "Inverted," the raise from 1 to 2 (or 1 to 2) is 10+ and the raise from 1 to 3 (or 1 to 3 is weak (typically less than 7). There is a gap for hands of about 8-9 points (too strong to raise to 3, but not strong enough to raise to 2).[Note: In some modern versions of this convention the raise to 3 is used as a "Mixed" raise to show 6-9--make sure you and your partner know if you are playing the jump as "weak" or "mixed."]
In no case should a minor be raised if responder has a 4-card major.
Here is an example of 1-2:
Here is an example (nobody vul) of 1-3:
When playing this convention, here are the discussion points:
Is it on by a passed hand? I'd say: YES.
Is it on after a double or overcall? I'd say: NO.
How high is the partnership forced after the raise from1 to 2? I recommend that you can stop in a partscore if either player's next bid is 2NT or 3-of-the-minor. Otherwise, it is game forcing. (Example of a NF auction: 1-2-2N-3). You must decide whether 2NT is passable or not by either opener or responder.
How light can the raise from 1 to 3 be? I suggest relying on the vulnerability. At favorable, it can be something like Jxxxxx and out. At unfavorable, it would be much sounder, maybe up to AQ10xxx and out. (See the note above about the option to play the jump raise as mixed).
How many cards to raise? In clubs, usually five or more. In diamonds, five are also the normal requirement, but it can occasionally be done with four (since a one-diamond opener is usually four-plus cards).
What does it mean if opener bids 2-of-a-Major after an inverted raise (1-2-2)? I recommend that it shows a stopper/concentration (it is pointless to show a 4-card major, since responder should never raise a minor with a 4-card major). After this show of concentration, if responder bids 2NT or 3-of-the-minor, it can be passed.
There are more bells and whistles which can be added, but in my KISS style, the above is sufficient to use Inverted Minors.
Inverted Minors are alertable: both the single raise and the double raise.
You can purchase Robert's webinar on Inverted Minors by Clicking Here.
last updated Jan 2023