Thanks, Ben for your analysis. Actually, I was sitting South, and the hand shown was my pd's. We were new partnership (well, played a couple of times before, but less than 20 boards as I remember) and I was not sure of what 4NT meant. So I bid 6♥ (I had 2 small ♠s, could be almost sure my pd had control on ♠). After 6♠, I was willing to go grand if my pd had first controls on black suits (void in ♠ and ♣A). My pd doubled and opps made 6♠ while we were cold on 7♥. As it was red to red, this was about 30 imps swing (assume opps wouldn't sac at 7♠). My hand was ♠xx, ♥AKQxxxx, ♦Ax, ♣xx. 4♠ bidder was void in ♦ and dummy was void in ♥ (no ♦ ruff).