[Hanoi5]

I was taught and I teach that holding a 4-card Major was a inhibitor to weak openings. The main reason for this was that a 4-4 (or 5-4) fit in that Major would be overlooked by partner as he wouldn't expect that many cards in that suit. I even noticed sometimes players who wouldn't pre-empt with 3 cards in the other Major.

However I've seen lately (last couple of years) an increasing number of breakers of this 'rule'. Is it because a 7-4 (or 6-4) hand with a good 7-card suit plays better in said suit than in the 4-4 fit? Is there a way to find about the possible Major? (Once I played 2♦ as weak with the possibility of a 4 card Major, 2NT would ask). Is there anything else to this (position, vulnerability, etc)?

[Fluffy]

There is no way to find about the major, its just that KQ109xx Jxxx is a 1 suiter while J10xxxx KQxx is a 2 suiter, you use your common sense.

[Bbradley62]

It also depends on whether you think "weak openings" are supposed to more descriptive to partner, to find the optimal contract, or more destructive to opponents to inhibit them from doing that. Such bids are frequently called "preempts", suggesting the latter.

[whereagles]

I've been opening weak 2s with side majors for the last 10 years and only once did we missed an obvious major suit game that would have been bid if I passed. We even open NV weak 2s on 5 cards on a regular basis.

It's really no big deal and it's easy to come up with some gadgets to pick up side 44 fits if responder is inv+.