[jallerton]

 1eyedjack, on 2013-December-24, 18:32, said:

I find it useful to split invitational 5-5 in the majors into two subcategories of strength, because I can construct hands with anything from about 7 to about 10 HCP and 5-5 in the majors opposite which game is possible but not certain (playing weak 1N). In practice with the extremes I would probably GF or weak t/o and pay off to the occasions when it fails, but it served to convince me in my own mind that, given the bidding space, and assuming no higher priority, it is nice to be able to distinguish a "weak invitational" from "strong invitational" hand with 5-5 in the majors. The latter I show by an immediate 3H response (3S response showing 5-5 in minors and stronger). The former (weak inv) I start with a 2C structure, which I will not go into here.

With most partners, I also start with a 2♣ structure on the 5/5 semi-invitational hands: it's called Stayman. If Opener shows a 4-card major, Responder raises. If Opener denies a 4-card major, responder signs off in 2M.

This is probably the biggest disadvantage of playing 2♣ as 5-card Stayman (which gains on some other hand types, but forces Responder to guess on weakish 5/5 and 5/4 majors hands).

[PhilKing]

 jallerton, on 2013-December-25, 15:39, said:

With most partners, I also start with a 2♣ structure on the 5/5 semi-invitational hands: it's called Stayman. If Opener shows a 4-card major, Responder raises. If Opener denies a 4-card major, responder signs off in 2M.

It's called underbidding.

[wanoff]

 PhilKing, on 2013-December-25, 18:09, said:

It's called underbidding.

Its actually called guessing.
With 10 cd majors I prefer to invite by 2C-2D-3M (6-4) or 2H-2S-3H (5-5)

[Jinksy]

 TWO4BRIDGE, on 2013-December-21, 08:04, said:

Some play the 3-level jumps to show the 5-5 majors :

1NT - 3H! = 5-5 invite
and
1NT - 3S! = 5-5 game force

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
In your structure, how would you show the 5-4 / 4-5 hands ?

At the moment, via an xfer then natural bid. 1N 2D / 2H 2S is inv+, F1, with opener's rebids all being major-oriented.

I like being able to take the non-GF 5-5 hands through Stayman, since it lets me hear opener's shape before deciding whether I want to invite or just sign off at the two level.