I used to play that a 2/1 new suit promised a 5+ card suit. A hand without a 5 card suit was treated as balanced (incl 4441 with singleton in opener). Such (balanced) hands were bid either by responding forcing notrump (with fewer than 16 points) followed by most likely correct game or by initially responding 2NT (with more than 15 points) (call it "Baron 2N"). Simple, but not very effective:
The problem appears to be exacerbated if you are playing Kaplan Interchange, otherwise known as Granville, whereby 1♥-1N shows 5+♠ and 1♥-1♠ shows 4 or fewer ♠:
Responder remains unsure of the best spot between 3N and 4♠ and now lacks forcing continuations to investigate
The problem appears to be further exacerbated if you decide to do away with the Baron 2N response in favour of Jacoby 2N (GF with 4+ card support for opener). There then remains the problem of how to describe the hands originally slotted into Jacoby 2N. Forcing NT does not work as you cannot catch up and show your strength.
The solution seems to be to relax the minimum length requirements of a 2/1 response. I never really understood the benefit of insisting on 5 card suit. Theoretically the continuations should be more accurate if the response is more narrowly defined, but I have not seen an example of advantage being taken of this inference. Anyone care to post one?
Finally, there remains one matter to be addressed: Even those who allow 4+ card 2/1 responses appear (in my experience) to regard it as a cardinal sin to respond 1♠-2♥ with only 4 card [H] suit. Does that principle go by the wayside now? If not what do you respond with:
Responder remains unsure of the best spot between 3N and 4♠ and now lacks forcing continuations to investigate
One solution may be to relax the definition of the Jacoby 2N response. Not sure why they insist on 4+ card support when an 8 card fit is guaranteed with 3 card support and there is substantial bidding space available should clarification be required.
Responder remains unsure of the best spot between 3N and 4♠ and now lacks forcing continuations to investigate