Inverted minor raises were developed as an improvement to natural fit responses to a minor, as well as to limit raises of minor suits. Here are a few reasons:
- The auction 1♣-P-2♣-P-P-P never happens. If neither partner has any major suit to mention, there's no way the opponents will let them buy the contract for 2♣. Thus, 3♣ would be a better preemptive response.
- A limit raise of 1♣-3♣ may be useful as an invitation to a minor suit game, but it is more useful as an invitation to 3NT. It is therefore best to leave as much room as possible to determine if this is feasible.
- With 6-10 points, 4 card support, and no 4-card major, bid the minor at the 3-level.
- With 11+ points, 4 card support, and no 4-card major, bid the minor at the 2-level. This bid is forcing unless responder is a passed hand. It is not a limit bid.
- Higher jump raises may also be used, but these are weak and indicative of very freakish distribution.
- First developed within the Kaplan-Sheinwold system, using a Weak Notrump and Five-Card Majors, the requirement for the single raise allowed for very few hands with only four-card support. The jump-raise with only four card-support was not allowed. I don't think either of these requirements have changed very much for most people.
- The single raise originally showed nine or more points, not eleven or more. I know that many pairs that combine the convention with Strong Notrump systems have higher requirements but it is not universal.
- Some pairs play the single raise as game-forcing. I don't point this out because I think it's sane, I don't, but because it is fairly common.
Opener's rebids after single (unlimited) raise Edit
- 3 of the original minor shows a real suit (4+ cards) and 13-14 points. This bid is not forcing
- 2NT shows a balanced hand suitable for notrump and 13-14 points. Opener often has just a three-card minor suit. This bid is not forcing.
- 3NT shows a balanced hand and 18-19 points. Opener may have a three-card minor suit.
- A new suit shows 15+ points, confirms a real opening suit (4+ cards), and at least 3 cards (often 4) in the new suit including a stopper. This bid is forcing.
- Playing a Weak Notrump, for which the convention was originally designed, the only rebid by opener that didn't force to game was three of the original Minor. A 2NT rebid showed a Strong Notrump (15+HCP) with no really weak suit. A 3NT rebid, for most pairs playing a Weak NT, was defined as showing a specific hand type. For many it was a minimum Strong NT, unsuitable for play in the Minor and discouraging for slam.
- Many pairs who play a Strong NT define the 2NT rebid as showing a balanced 12-13 and jump to game on a balanced 14-15. This makes it difficult to show the 18-19 HCP hand.
For the rest of the auction, the following agreements are in place:
- Any bid of the agreed minor or 2NT indicates a minimum, given the preceding bids, and is not forcing (unless 3NT has already been bid, in which case game must be reached).
- A bid of 3NT is a natural sign-off.
- Any other suit bid is forcing and shows stoppers below 3NT
Opener's rebids after a jump (preemptive) raise Edit
- Pass -- this is the usual action.
- 3NT is possible with a balanced hand and 18-19 points.
- A new suit is a game try, showing a strong 4-card suit.
- 4 of the agreed minor is a further preempt and must be passed.
- 5 of the agreed minor is a sign-off in game.
A word of caution Edit
- Jump (preemptive) raises may not be optimal with a balanced hand and honors in the unbid suits. Prefer 1NT in this case.
- ↑  Response to One-Level Opening Suit Bids : Three-level jump raises not in competition which promise less than invitational values
External Links Edit
- worldwidefolks.com competitive bridge: inverted minor raises
Single raise - Jump raise