Question:
Is it okay to open a 4-card major to avoid a reverse.
Answer:
First, let me say NO and then I will contradict this later. Without a 5-card major, open your best minor. With a 4-card or 5-card minor and a 4-card major, open your minor. If you have 4 hearts and partner bids 1 spade, don’t be afraid to support partner with 3-card spade support (especially if the other minor is 2 small) otherwise bid 1NT, limiting your hand. If partner bids 1 heart over my minor opening, and I have 4-3-3-3 distribution, I tend to bid 1NT to limit my hand. With a 4-3-2-4 hand, I will bid 1 spade showing partner that I have 4 spades and a 4-card or longer minor. He is free then to support my minor. If you open your 4-card major with a 5-card minor, partner will never believe you are 4-5 in the major/minor.
Now the contradiction. If the auction has gone pass-pass to me and I have a light opener, I will open a 4-card major over a 4 or 5-card minor, if my major is a better option for partner to lead should my left-hand opponent win the auction. For example, AKxx in major verses Q10xx in the minor. Second reason is that if my left hand opponent has the other minor suit, it is harder for him to come into the auction over a major opening than over, say, a 1 club opening. If you do open a 4-card major, you must be prepared to play a 4-3 fit or occasionally a 4-2 fit. If you uncomfortable with that, then open your minor.