Interesting idea. Let me see if I have this exactly right.
After Responder shows diamonds (4♦), Opener can bid 4♥ as a spade flag, albeit without shhowing extras necessarily. This allows Responder to simply bid 4♠ as a mild slam try, or, after learning of the fit, take some other more aggressive action, including 4NT (RKCB), presumably 5♦ as RKCB for the diamond suit secondaries (spades still agreed), or Exclusion 5♣/5♥, or possibly a quantitative 5♠. If Responder opts mild only (4♠), Opener could continue on with 4NT (RKCB), 5♦ (RKCB diamond secondaries focused), or maybe 5♣/5♥ as something else (Empathetic Splinter?).
If Opener has a diamond focus, he flags diamonds via 4♠. Responder can suggest a signoff (4NT or 5♦). I'd suggest 5♣ by either side (5♣ immediately by Responder or 4NT-P-5♣ by Opener) as Last Train, myself, with 5♦ a decline again, 5♥ accept with 2, 5♠ accept 2 with Q, 5NT accept 3, 6♣ acept 3+Q. Something like that.
Opener can also bid 4NT as natural.
From: A.H. (may want privacy)
Subject: about the bidding
Date: Sat, 12 Jul 2008 00:38:58 +0000
this is alex, i am the fan of your book "Cuebidding At Bridge ", thanks for sharing those bright ideas,
I have some think about 2NT--3H--3S--4D, on page 154, I am currently using transfer after the sequence like this, thinking may works better
4H Now opener's 4H is trsfer to 4S, flag of Spades,perparing stop at 4S or strong hand will bid 4NT
as RKC for Spades.Responder can refuse trsfer if he has stronger hand instead of mildly slamish.
if responder bid 4NT it is RKC of spades.
4S Now it is flag for D, RKC . Or we can use as D flag, but not a very good hand to bid RKC,
or strong hand(will bid 5C as RKC if responder signoff)responder can rebid 4NT as signoff , 5C is