Yin calendar - Inreki

…Although the specific ceremonies are unclear, it took about 360 days for these five types of rituals to complete one cycle, and one cycle was counted as one ritual. The years a king reigned were expressed as 13 rituals, and the time was indicated by a ritual calendar. This calendar was based on the lunisolar calendar, with leap months added to adjust to the movement of the sun (the Yin calendar). Star observations were also conducted. …

*Some of the terminology explanations that refer to the "Yin calendar" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…具体的な儀礼などは明らかでないが，この5種の祭祀が一巡するのに360日前後を要し，一巡するのを1祀として数え，王の即位年数を13祀などと表現し，また祭祀表カレンダーによって時を示した。このカレンダーの基礎は太陰太陽暦で，閏月を設けて太陽の運行と調節した(殷暦)。また星などの観察も行われていた。…

※「殷暦」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報