How do you bid the grand?

[johnu]

Ah, why check for A and K when you hold all 8 of them.

1♠ here is RKC

You always check for aces and kings on BBO because it is the law.

[Gilithin]

I'm not sure how the field makes 4♠+1 when ops have the top 5♠. Also while I may pass with 5, 6 is a different matter.

On average you don't expect the extreme hand you are suggesting with opener holding 28hcp

You are proving the point of choosing Responder's bids based on Opener's hand. I specifically wrote the original opening hand for the section you are quoting, so Opener holds ♠AKx. Spades break 3-1 and without an entry to Dummy 3NT only gets the 8 tricks you started with. Meanwhile Dummy is worth 3 tricks to the rest of the field playing in 4♠. Finally, a Yarborough with a 6 card major is not such an unlikely hand opposite 28+ balanced.

[mw64ahw]

You are proving the point of choosing Responder's bids based on Opener's hand. I specifically wrote the original opening hand for the section you are quoting, so Opener holds ♠AKx. Spades break 3-1 and without an entry to Dummy 3NT only gets the 8 tricks you started with. Meanwhile Dummy is worth 3 tricks to the rest of the field playing in 4♠. Finally, a Yarborough with a 6 card major is not such an unlikely hand opposite 28+ balanced.

I think I'd need to run the probability distributions to get a good idea of what is optimal. Taking the other extreme, your example hand can go down 2 when spades break 5-0 whereas 3NT will only go down 1. And a Yarborough is still a low probability event opposite 28hcp