mikl_plkcc, on 2025-April-26, 12:09, said:
And I don't intend our 4SF as exactly invitational at the 2-level (our agreement is that 4SF is 4 spades at 1-level, F1 at 2-level, GF at 3-level), the 4SF bidder can bid on the show GF strength.
My judgement was that my hand was enough to invite in case of a 5-3 major fit, but not strong enough to play 2NT, due to the 2 doubletons adding 2 distributional points, and NT hands are evaluated using HCP only.
The standard approach with 4 spades and 3 card heart support would be
#1 raise openers suit with less than inv. values to the 2 level
#2 bid spades, followed by by making a jump raise to the 3 level
#3 use FSF to create a GF seq followed by bidding hearts, if opener
showes min., fast arrival applies
This approach is the same for either FSF as GF or inv.+.
....................................................................
If opener opens with a minor, opener can and should show a fragment,
i.e. secondary support, if holding more than min.
I would also argue, that responder showes a suit oriented hand, if
he showes support for openers minor, i.e. 5422 / 5431 shape.