Diana was South and took the blame here for not bidding 7NT but I don't see it.
If she keycards for clubs (how to do that by the way? I'm not sure if we agreed to use 4♦ for this) she still wouldn't know what to do if I turned out to have only one keycard.
If she cuebids 5♦ after my 4♠ bid I suppose I would collaborate somehow, probably by bidding 6♣, but I don't see how that would lead to a confident 7NT. For all she knows my cuebid could be based on Jxx-x-Kx-AJxxxxx in which case 7♠ has better chances.
The easiest solution is if I open 1♣, but the hand is a tad light for our style. In the other room, Lorenzo passed. Maybe that is better. It is certainly my style to preempt with this hand but I probably preempt too much, yesterday we got bad results every time I preempted.
Finally, it might become easier if I make a more positive bid over 3♠. I suppose 4♦ would show something like this (although, again, it could have been based on a hand with better spade support and worse clubs). But this wasn't discussed and probably wouldn't lead to a confident 7NT).
If I pass it starts 2♣-3♣ and we will probably get it right. If I open 1♣ Diana might just blast 7NT directly.
What do you think?