The Inverted Minor convention 'inverts' the classical meaning of a single and double raise.
A single raise is forcing, showing at least invitational values; the jump raise is
preemptive.
Jump Raise
The requirement for a jump raise in a minor is:
Five card or longer support for opener's minor
0 - 9 HCP ( High Card Points )
No 4 card major
Some distributional value ( not 5-3-3-2 distribution )
In addition, some players have an additional restriction of no outside Ace or King.
This will decrease the frequency of the bid, but give partner an exact picture of the
defensiveassets of the partnership.
Alternatively, you can have an understanding that the jump raise will show no more than a
King outside.
Partner will, in this case also, have a pretty good picture of the defensive assets.
For example, if you have pushed the opponents to the five level
- partner will double with 3 tricks
- partner will pass with 2 tricks ( partner is not sure that you have a trick )
- partner will know that you cannot beat the hand if he has 1 trick. Partner may
sacrifice under favourable conditions
The important thing is to have an understanding about the precise
meaning of the jump raise.
Single Raise
The requirement for a single raise in a minor is:
Four card or longer support for opener's minor
10 or more HCP
No 4 card major
Opener rebids as follows:
- 2 of a suit: bidding stoppers up the line
- 2NT: 12 - 13 HCP; stopper in both majors; non forcing
- 3 level in another suit: game going hand with shortage in the suit bid
- 3NT: Balanced 18 - 19 points ( assuming that opening 1 NT range is 15-17 pts
)
In competition
After a takeout double:
- redouble shows a good hand
- 2NT is a limit raise of partner's suit
- Single raise is weak (6-9)
- jump raise is preemptive (0-5)
After an overcall:
- Single raise is weak (6-9)
- Cue bid shows limit raise or more