Michael and I play MAFIA style responses; that is, if partner opens 1 or 1, we respond with our 4-card major even if we have a longer minor, regardless of our hand strength. This leads to an interesting phenomenon: not only do 1-2 and 1-2 deny interest in a major-suit contract, 1-2 does also. In our system, all three of these sequences are treated the same way: responder shows a 10+ point hand, and subsequent bidding is aimed determining the playability of 3NT. (When I play Polish Club variants, 1-1 is artificial and 1-2 can also be treated the very same way.)
Our inverted-minor agreements are impacted by two other tendencies of our system that might be unfamiliar to 2/1 players: One, we open most 11-counts in first seat (as a result, we rarely go below 11 in thir seat either, and we don't need Drury -- if a hand would be a 3-card limit raise opposite a 3rd seat opener, we open it in 1st.) Two, we play 1-2NT and 1-2NT as natural and forcing, promising stoppers in all 3 unbid suits, not necessarily denying a 4-card major. The 2NT bid shows either a (good 13) 14-15 point hand, or an 18+ monster; with a flat 16-17 and no 4CM, we jump to 3NT. I actually regard the popular "11-12, no 4CM" 2NT reply as almost unplayable; responder rarely has all the stoppers he needs, and opener has no room to explore without committing the partnership to game.
In this context, Inverted Minor sequences handle all of responder's balanced 11 to bad 13s, as well as responder's stronger balanced hands that are missing a stopper, and responder's strong raises of the minor.
The 1m-3m jumps are typically 4-7ish, occasionally weaker. With most of our 8 HCP hands with support for opener's minor, we risk a 1NT response, and retreat to our minor if the opponents double or overcall. (Yeah, matchpoint addicts. I know.) You could put the 8-10 range into a Criss-Cross style 1-3 bid, if you preferred.
Golden rules of inverted minor auctions
These few principles sum up our rules for our continuations:
2NT and 3 of our minor are invitational, by either partner.
2 of a new suit is forcing and shows a stopper in that suit.
3 of a new suit (on or after responders 2nd bid) is forcing; if that suit could not be shown at the 2-level, it asks for a stopper; if it could be, it shows/asks for a half-stopper.
4 of our minor is Blackwood. (To be honest, I'd rather agree that 4 of our minor demands a cuebid, and use 4 of the next higher suit as ace-asking if that bid is idle. But this is our current agreement.)
Other bids beyond 3NT are cuebids for the agreed minor (and in our style of cuebidding, 4NT is going to be a passable bid when we get there.)
That just leaves two special bids by opener:
Since 3 of our minor is invitational, if we have a good minor-suit-oriented hand, we rebid the other minor, 1-2-2 or 1-2-3. This is usually natural (if we don't have the majors stopped, we almost always have the other minor stopped!) but the point of the bid is showing extras and serious suit orientation.
Opener's jump shift rebid is a splinter, showing plenty to force to game and asking responder to cuebid. (Reponder may still opt for 3NT after 1m-2m-3M.)
When the auction starts 1m-1M-1NT, our version of Checkback Stayman explicitly asks opener if he is minimum or maximum since 1NT is wide-ranging (lots of 11s other people didn't open, on up to a good 14.) After 1-2, the same thing happens -- opener can have anywhere from 11 upwards -- and we need to handle the auction carefully to judge whether to continue on to 3NT or not. Here is opener's "notrump rebid ladder":
With 11 or a bad 12, we don't want to give responder any encouragement. We show a stopper with 2 of a major, and if responder's rebid is 2NT/3m, we drop him.
With a good 12 or 13, we use the classic invitation, 1m-2m-2NT. Responder passes or bids 3m to refuse, bids 3NT or 5m to accept, anything else is slam exploration. (Responder is expected to accept with a solid 12 count.)
With 14-17, we know we want at least game, but we need to leave room for responder to explore if he wishes. We show a stopper with 2 of a major. If responder rebids 2NT we raise him to game. If he explores for a slam we happily cooperate.
We reserve the jump 1m-2m-3NT to show an 18-pointer, balanced but too strong to open with 1NT.
Modifications after 1-2
The only wrinkle here with the "inverted minor non-raise" is that we no longer have 1-2-3 available as a semi-artificial forward-going bid. Opener's rebids of 2 and 3 are both natural and nonforcing. With a strong hand and no stopper, you jump to 3 or 4 (the latter setting trump and starting cuebids).
1-1 in the MAFIA style
As I noted in the introduction, I started playing extended inverted minors when I was playing a Polish club. In SA or 2/1, the 1 response is natural. We use this bid with a long diamond suit and no 4-card major and 6 HCP of course; but our most common reason to respond 1 is a desire to bid notrump but either out-of-range or lacking a stopper. Our 1NT response to 1 is 8-10, and 2NT is forcing as described above; so a balaced 6-7 or 11-12 without a 4-card major often responds 1 to 1. Opener's 1-1-1NT rebid confirms stoppers in both majors (he may even be 4-4-1-4!) while opener's 1-1-1M says opener either has a club-major two-suiter, or is wide open in the other major and unwilling to declare notrump.
or 1
, we respond with our 4-card major even if we have a longer minor, regardless of our hand strength. This leads to an interesting phenomenon: not only do 1