rhm, on 2019-August-11, 16:03, said:
It is a hand which ranges from a minimum response to a hand just short of an invititational jump rebid.
Same suit rebid shows a six card in the range between 5-10 HCP
If 4th suit is forcing to game there is often no other way to show such hands.
Same suit rebid by responder is not encouraging, but this is not the same as drop dead.
Drop dead bids tend to occur only if opener has strictly limited his hand like after a notrump bid.
On the actual layout opener can see that 5♦ might have play opposite KTxxxxx in diamonds and little else.
But opener can only evaluate his hand properly if you rebid your six card suit. 2NT will not do and the suit is not good enough for a jump rebid in diamonds.
If there is no fit you want to stop in 2♦.
Rainer Herrmann
It's not nonsense at all, don't assume your system is played by Brits, many people here DO NOT play 4SF FG at the 2 level. 2♦ is about 5-8 to many here, either you bid 3♦ with 9-11 and the suit isn't good enough for that or you bid 4SF and follow with 3♦ if you play it NF (which is what we would do).
Rebidding 2♦ will attract a pass with many non fitting 15-16s where 3N is good, Axxx, Qx, A, AQxxxx for example (how good is that hand opposite ♦KQJxxx and out).