In modern times, the best know method of Japanese bookbinding is fukuro-toji, also known as a stab binding or pouch binding. However, another method, now known as tetsuyōsō (畷葉装, 'multi-section binding'), was commonly used throughout the Heian and Kamakura periods to bind volumes of prose. This style of binding involved folding sheets of paper into sections similar to a Western style binding, then sewing them together with a unique and complex stitching pattern.
See how it works in the video below.[1]
Traditionally, Japanese paper was made out of bark from the kozo (Japanese mulberry) plant, so it is sometimes called kozo paper or mulberry paper. Another name for it is washi (和紙), which translates literally to ‘Japanese paper’, although in many English speaking places it is just called ‘washi’. It was often dyed in colors and decorated with materials such as mica and gold leaf to provide a beautiful canvas for calligraphy or hyōshi (表紙, ‘cover papers’) for a book.[2] Murasaki Shikibu recounts in her diary her pleasure at receiving colored kozo paper while serving Empress Shōshi,[3] so it was a coveted luxury even among the social elite of Heian Japan.