The Interior Grosgrain Ribbon Belt: Vogue 8013, 1952
You see here a not quite lost construction element. I actually first saw an inside grosgrain ribbon belt on a modern designer name sewing pattern, but you are more likely to find them in vintage patterns.
The idea is to take a stable ribbon, like grosgrain, and shift some of the strain of wearing at the waistline from the fabric to the ribbon. After all, the body necessarily expands and moves at the waist when sitting, etc. This kind of belt is useful especially if the fabric is lightweight, the silhouette is fitted, the skirt is voluminous, and there is no button or other fastener at the waistline itself. This is an early 1950s patterns, so it has an hourglass shape and a long, flared skirt that is also pleated. Although the button placket extends into the skirt, there is no button at the waistline, and the pattern is shown with a belt to wear over the dress.
As you can see here, the ribbon is finished at the ends by hand, fitted out with hooks and eyes and is then tacked all around the waistline. Since this dress is worn with a belt on the outside, the tacking will not show. The modern pattern I made with an interior belt only asked that it be tacked at the seam allowances, but that did not work well: the interior belt drew the dress close to the body only at those points. The results were odd and and the vintage version here strikes me as far more useful.
I am copying this pattern at the moment and hope to show you the finished results soon.