[Siegmund]

I think the yeti got this one right. A void in the opp's suit, a side 6-card suit, and "negative defensive tricks" (not only will we take 0 tricks on defense, we know that partner has less chance of defensive diamond tricks than he thinks he does) - there is literally no hand less suited to defence than this one. (Well, OK, the same hand with a sixth spade.)

If North had some ordinary 5-0-5-3 with 6HCP, then we'd be in territory where somebody might bid 5S absent the hesitation, but is going to be constrained by the BIT UI.

Quote

"So, if you weren't going to let them play 5H, why did you only bid 4S the first time?"

Seriously? You can ask that question if the majors are reversed and you're raising hearts to immediately preempt a 4S bid by fourth hand... but I don't think anybody is going to leap to the 5-level just to shut out a 5H bid here. There's no guarantee fourth hand will bid 5H at all (maybe he'll bid clubs, maybe he'll cuebid, maybe he'll double).