Orihon (Japanese: 折本, Hepburn: Orihon, Japanese pronunciation: [oɾihoɴ]) is a style of Japanese codex—a historic precursor to modern books—with an accordion-folded structure, which is known also as concertina binding. Based on the Tang dynasty jingzhe zhuang, or “neat-folded paper binding," this codex style was developed during the Heian period.[1][2]