Source:
www.vcbridge.org 
Do you sometimes have difficulty reaching close games or slams when you have a minor fit? Inverted minors can be a great help, but perhaps 3-Way Minor Raises can even be more helpful. Paul Ryan, one of my recent partners, devised the basic concept of 3-Way Minor Raises, while some of the suggested variations in the meaning of the responses were proposed by Sharp Fang.
The basic premise of 3-Way Minor Raises is very simple. After your partner opens one of a minor, you play that a jump to three of partner’s minor by responder is non-invitational, you play a simple raise to two of partner’s minor is a game-forcing raise and a jump-shift into the other minor (called a Criss-Cross raise) is an invitational raise of partner’s minor — 1
-2
or 1
-3
.
Playing both invitational and game-forcing minor raises allows the partnership to know immediately how strong responder is—with just invitational values or at least game values. After a two-level game-forcing raise, you can leisurely investigate which game to bid or look for a slam. With invitational values and five-card trump support, a Criss-Cross jump “raise” can be both descriptive as well as somewhat preemptive as there are times the opponents have major suit fits and enough strength to be a nuisance if given the opportunity to make a low-level overcall.
As to the jump raise to three of partner’s minor, it has been defined as non-invitational but a better way to describe it is that a jump raise is constructive when vulnerable and more on the preemptive side when not vulnerable. Then, when not vulnerable and you have five-card minor support and no stiff or void, responder might well choose to bid 1NT with constructive values rather than jump to three of the minor as game might be missed—or a lower seven-trick contract.
Here is the suggested bidding structure playing 3-Way Minor Raises
1
-1NT = Shows 8-10 HCP (non-vul, perhaps replacing a non-existent constructive minor raise)
1
-2
= Shows at least game-going values and usually five-card club support
1
-2
= Shows invitational values and at least five-card club support (Criss-Cross)
(sometimes might have more shape than HCP when non-vul)
1
-3
= Shows at least five clubs and if vulnerable, is constructive; if not, usually preemptive
1
-1NT = Shows 6-9 HCP (non-vul, perhaps replacing a non-existent constructive minor raise)
1
-2
= Shows at least game-going values and usually five-card diamond support
1
-3
= Shows invitational values and at least five-card diamond support (Criss-Cross)
(very rarely might have much more shape than HCP when non-vul)
1
-3
= Shows at least five diamonds & if vulnerable, is constructive; if not, usually preemptive
When vulnerable, responder should have no doubt which of the three raises is appropriate, but he must remember that there is no preemptive raise option open to him when he is vulnerable.
When not vulnerable, sometimes when responder has a singleton or void (unsuitable to respond 1NT) and good trump support, he may have to decide whether to make a slight overbid with an invitational raise (Criss-Cross) or a slight underbid with a preemptive jump raise.
One thing to remember is that when you are not vulnerable, after a Criss-Cross invitational
minor raise of clubs (2
), responder will often have a chance to show minimal values below game, so you might be a bit light with a distributional hand, while after an invitational raise of diamonds (3
), there will be no 2nd chance to show (sub)minimal values below game, so when making a non-vulnerable invitational raise of diamonds, responder would be wise to have full values.
