The existing belts made in the Edo Period had unpolished leather for the core (the condition of the leather when it was new is unknown, but it looks light-green, translucent and hard in many cases), and a piece of thin leather was folded and wrapped so that it was joined at the center of the back.
江戸時代の遺品は練らない革(新しかったときのことはわからないが、現状ではあめ色の半透明な堅いものに見えるものが多い)を芯にして、薄い革を折り込み、裏面中央で合うようにして包む。