[DavidKok]

No, in fact you shouldn't. With that first hand, the most likely game is 4♠, and even in partscores spades have the advantage over clubs (of being a level lower, and scoring higher). This does depend on partnership agreement, but most people would prefer to show a major suit with a weak hand. If you are in the slam zone the situation is different.

[undoubling]

I note so far that only 1 responder to this topic has even mentioned Gerber as an answer. In my experience, MOST of the partnerships that I know of (yes, intermediate or lower) play Gerber over FIRST or LAST NT bid, so when the 3NT is pulled to 4C, it asks for ACES and is INTERESTED in a Club or NT slam.

[Stephen Tu]

undoubling, on 2020-October-19, 10:15, said:

I note so far that only 1 responder to this topic has even mentioned Gerber as an answer. In my experience, MOST of the partnerships that I know of (yes, intermediate or lower) play Gerber over FIRST or LAST NT bid, so when the 3NT is pulled to 4C, it asks for ACES and is INTERESTED in a Club or NT slam.

Better players have a strong tendency to use Gerber in far fewer sequences, and much less often, than intermediate and lower players. Usually it's only as a *jump* to 4c over a natural 1nt/2nt opening/rebid, or immediately after a 2 level Stayman response (playing the Baze scheme of continuations after 1nt-2c-2x). Pulling 3nt to 4c is usually played as natural forcing, or on some other auctions might be a cue for clubs.

That said, playing this particular sequence after a forcing 3c as rkc minorwood isn't awful IMO. I prefer kickback though.
Non-jump 4c over 3nt as some form of ace-asking really should not be assumed without prior agreement, and if agreed should only apply when in a GF clubs trump auction.

[helene_t]

I said 4♣ can't show slam interest if 3♣ was non-forcing, but maybe something like
xxxx-Qxx-x-Kxxxx ?
Now that opener has implied a 1-3-4-5 shape, my weak spades are no longer a liability so I suddenly have slam interest.

[Douglas43]

DavidKok, on 2020-October-19, 08:36, said:

No, in fact you shouldn't. With that first hand, the most likely game is 4♠, and even in partscores spades have the advantage over clubs (of being a level lower, and scoring higher). This does depend on partnership agreement, but most people would prefer to show a major suit with a weak hand. If you are in the slam zone the situation is different.

Thanks DavidKok, comment appreciated. The choice of 4cM / 5cM method probably affects this area of bidding more than I expected. Partner is less likely to have a 4 card spade suit playing 4cM.

[mycroft]

mycroft, on 2020-October-18, 09:59, said:

[1] 2♦ reverse shows extras
[2] I play Lebensohl after reverses, so 3♣ shows GF opposite minimum reverse, so a decent 8-ish.

bluenikki, on 2020-October-18, 11:44, said:

QJxx
QJ
-
8765432

If you lebensohl, how is opener to know you have this rather than

QJxx
QJ
Jx
65432

Surely you're not expecting me to Walrus the first hand, and send them both through 2NT?

Quote

The first is a *good* hand. 11 Goren points. Just unplayable in anything but clubs.

And totally eligible for a direct 3♣. Actually, with 3NT basically out of the picture (can't guarantee an entry to the long clubs), totally eligible for a direct 5♣; don't want to go minus in an unmakable slam, you know.

Quote

Your point of view is that minor-suit hands must resign themselves to minuses when pluses are easy.

No, I want to be able to survive in 3♣ with your second hand, or with QJxx KTx Jxx 8xx, for that matter. I want to be in game with your first; 3NT if I have an entry, but you've carefully avoided even 9765432, so probably 5♣ is safer.

Also, what others have said about very quiet opponents with, at worst, two 8-card fits and a 9-carder.