The books of the old book type take on a conversational style and lack correlation between stories, while the books of the similar book type, which are thought to have included some additions and improvements during the Middle Ages, are divided into six sections which are based on themes.
談話形式を取り、連関性を欠く古本系に対し、中世に改編・加筆されたと思われる類聚本の方では内容に沿って六部に分けている。