Douglas43, on 2025-April-27, 02:46, said:
The only exception is 4-4 majors and 15+ hcp, when you open 1H.
We have to have exact rules on which suit to bid in order to have infererences because the other suits are not bid, such that we can work out the exact number of cards in each suit when trying to find a fit, and in competitive auctions.
For example, in a 5-card major system, if 1♣-1♦-1NT does not deny a 4-card major, responder must use checkback Stayman whenever holding a 4-card major to avoid losing a fit, similar to a 1NT opening; if 1♣-1♦-1NT denies a 4-card major, responder can raise direct to 3NT holding 13 HCP 2=4=5=2 and a ♠ stopper without the need to disclose the ♥ holding.