I am late in adding what I would do at the table. Our options are limited and we cannot expect a co-operative auction from partner very often, since we are looking at better and longer trumps than we needed to have (tho not by much, and this holding won't be a surprise) and, more importantly, we own 1st round control in all side suits.
There is no way that he is ever going to be the one to bid grand merely because he has, say, Axxx in diamonds
Grand is great opposite KQx QJxxx Axxx x...pray tell me how we can construct an auction that allows him to evaluate that, but not AKx KQJxx xxxx x?
I know, I should never give examples because there is always someone who claims that they and their partner always get these right.
I would choose 5
♠ even tho partner has no idea about exclusion. Even partner will know this must be a void and an attempt to look for grand.
We may not get there.
But, if he cues 6
♣ along the way (I am probably deluding myself that he can), that would imply interest and he will downgrade spade cards and upgrade the diamond A, so I will definitely bid grand over 6
♣.
If he bids 5N, I have no idea what that 'should' mean...surely even a partner to whom exclusion is a deep mystery can't seriously think we want to play in notrump?
Again, I would take this as interest but with no club control...indeed, with an expert partner (which I suspect I don't have due to his or her ignorance of a common gadget), I would expect 5N more often than 6
♣. So I would bid grand.
If, otoh, he goes back to 6
♦, I am finished. Indeed, since I expect my 5
♠ call to cause temporary paralysis over there, as he tries to figure out what madness has possessed me, the tank alone will bar me
A non-regressive move, no matter how slow, won't bar me at all.
On the third hand (since my first and the other one are taken already) I would just blast 7
♦ if I had no respect for partner at all.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari