msjennifer, on 2016-September-04, 01:30, said:
As per Super Precision,3S ,if made with NT in mind, denies a guard in H.To ask for a spade guard he bids 3H not 3S. Obviously,opener can not have a heart suit as he would either have bid it or doubled the 2S bid. I give one example( without intervention),
1S-2C
2S-3D. Denies a guard in Heart suit .It also may be an advance Diamond cue bid with S support,( This will be made clear later if responder bids 4S on openers bid over 3D.)
Whether to adopt this method or not ,of course,is upto individual preference or liking.
Your example with two unbid suits in uncontested auction, is quite a different situation from dickiegera's question, though.
Seems to me your 3D is basically "natural" (perhaps 3+ if no other suitable bid).
Would not be surprised if opener sometimes has a 4 card diamond suit (e.g. AKJTxx x xxxx Ax).
While responder might also be 4-6 or 4-7 i minors with a super-strong slam-interest hand, and rebid his clubs next round.