A reader from England posed a problem hand.
The issue: Opener has extras with six diamonds and a stiff club, but not THAT much. Responder has five clubs, four spades, 2-2 in the reds, and extra,s (15 HCP), but not THAT much, but he has no honors in clubs. Slam makes easily, but how to get there?
Opener starts 1D, and Responder bids 2C. Whether this is Golady and artificial, or real, Opener needs to be able to show the stiff club and extras. If he can, slam is easily bid.
When 1D promises a stiff or void (unbalanced diamond), which is how I like to play, this is easy. With a simple non-GF style, with real club bids, as I play with my wife, a 3NT rebid worked well. My wife, given Responder's hand, just bid 6D next.
Golady works also. 3H or 3S would be auto-splinters (extras, shortness here). A choice needs to be made as to how to show the stiff club. 3NT is still an option. Or, 3D (because 3C shows diamonds also) works well. Or, if 3D is used to show a minimum without shortness, say, then 3C shows either extras or a stiff, 3D asking.
I like 3D as the auto-splinter in clubs, personally, but that might be because I like my diamond openings to be unbalanced. If not using that method, I think 3NT as the club splinter (4C as a BIG club splinter) makes sense.