Late 70s Vintage Cornflower Blue Gown with Empire Waist Detail and Back Chiffon Flutter Sleeves/Sashes/Cape

20.5ish bust
12.75 strap to underbust (although underbust seam is angled)
18 waist
29 hip
57.5" long

Some stretch to the Poly
What an incredible find from the late seventies - I always get excited over great plus vintage. Back then they did half sizes to denote plus, so this should have been equivalent to about a 16. Surprisingly I think it is close to a modern 14 or 16.
It looks VGUC - I see a small possible water spot on the left bust and 2 toward the bottom of the left chiffon sash in back. But these are only really visible when using really harsh Flash photography. You could also try your luck with a good dry cleaner. Under the chiffon layer is a basic tank style dress.

This item is sold from a vintage boutique in Cleveland, Ohio.