mikeh, on 2015-January-09, 14:06, said:
No good player would play that 4♣ 'set clubs'. That would be absurd.
Give opener AQx A Qx AKJxxxx and responder either of xx xxx AKxxx Qxx or xxx xxx AKJxxx x
Would the bidding be different through 4♣?
On the first hand you want to play in 7♣ but on the second, 7♦.
No, the reason 4♣ set clubs, for you, was to allow 4♠ to be a cuebid by responder, rather than, say, bidding out his 4=2=5=2 shape, and (even more absurd) 5♦ to be a cue by opener showing a VOID!!!!! Wow.
The way to avoid this sort of thing, and it happens all the time on BBF with several posters, is to try to blank out one of the hands and imagine the auction as if you were holding the hand you haven't blanked out. Forget that responder has Kxx xxx AKxxx xx. Just imagine you'd opened 2♣, the auction proceeded to 4♠ and ask 'what would that mean if I couldn't see his hand'?
When asking that, ask if there are layouts where natural makes sense.
AKQx Ax x AKQxxx opposite Jxxx xx AKxxxx x
How does the auction start? How does it go at the 4-level? How do you find spades if 4♣ sets trump?
Timo nailed it, btw, and I upvoted his post.
Although at first I though that 4♥ should be the bid as 4♠ is too risky, and might be taken as natural, I later realiced that 4♠ as natural makes very little sense (upong reading phoenix reply) and I mover towards the cuebid camp, still I understand that the "if a bid can be natural it is natural" rule is too strong, so some players will play 4♠ as nat, even if clearly not best on this particular situation. But I would not.
Phoenix might have nto elaborated his respone deeply, but you are taking his words the wrong way. As it is obvious for him (and everyone else) that 4♣is a very strong suggestion to use as trumps, but doesn't really set up trumps. How do I know this? because he did bid 4♠ over 4♣, if 4♣ showed self sufficent suit he would bid 4♦.
Now why is he loving the diamond void and getting to grand slam without heart control is not really great and is likely influenced b the knowledge of the full hand.