This is an obi (sash) for Ichimatsu dolls. It doesn't have a core, but the fabric is firm, so it will hold its shape nicely even when tied as is. It's a so-called "hiruya obi," which means it's made by sewing together different fabrics for the front and back. The front is a yellow-toned tsumugi (silk), which was unpicked from a kimono and has some creases at the edges. The back is a subdued vermilion with white patterns in places. This is also likely tsumugi (silk). It's a stylish combination of obi, and it has a more fashionable feel compared to plain crepe, etc. I think it's cute no matter which side is shown, or even if you tie it so both sides are visible. Approximately 8cm x 117cm I think it's a suitable size for dolls around 42cm to 52cm, but please check the actual size before purchasing.