johnu, on 2022-July-01, 15:25, said:
1. A cursory search of Unassuming Cue Bid shows that 3+ card support for opener's overcall suit is specified. A close inspection of this hand shows Qx as support which is not 3+ card support. Partner may think spades is a good suit to play in when it is not. What are you going to do when partner jumps to 4♠ and you haven't showed diamonds yet?
2. You are guilty of double dummy bidding. It's easy enough to see double dummy that with near perfect cards and a key club void, 7♦ is on a finesse on 23 HCP. Give West a more modest shape like 5332 or 5422 and do some simulations.
3. Bidding 3♣ instead of 2♦ means you can't introduce diamonds until the 4 level. I doubt that any high level pairs play that a new bid of 4♦ shows a solid suit and denies 3+ card spade support. Most would play 4♦ as a cue bid showing a big hand with spade support since you didn't start with 2♦.
Thank you and I can answer that: what drives the bid is the solid suit of ♦ and a hand that is worth 19 / + points and it is expected that in this way we can show strength and distribution while keeping the bid low. As for the hypothesis that the partner jumps to 4 I have not even considered it since S has opened and W has simple overcalled and I have a very strong hand. Regarding the support Qx can be equivalent to xxx but a card cannot prevent me from using and completing the UCB convention (which I adopted talking about it in "Raising the suit of opponent" in GBD in June 2016 ") with the "Ultherior Extension of UCB "which happens a few times. The bidding and the relative development allows us to stop at 5 ♦ after the RKB when we discover that it has only one keycard but proceeds automatically giving the unexpected 5NT that projects the game up to grand slam. But as you can see I say almost 6 ♦. On the other hand, what can S have if not the missing honors with a hand made of Kings in the major suits (to ♣ it does not matter because we have the void) that directs the planning play?