The Xuanming calendar (宣明历), also known as Senmyō-reki or Senmei-reki in its Japanese version, was a Chinese lunisolar calendar. It was used in China during the 9th century as well as in the Koryo kingdom in Korea; in Japan it remained in use from the late-9th century to the late-17th century.
The calendar was imported into Japan in 859. The earliest record of this calendar being used in Japan is in the 8th month of the 3rd year of Jōgan (861) during the reign of the Emperor Seiwa. It would continue to be used until 1684, after which it would be superseded by the Jōkyō calendar, the first calendar developed specifically for Japan; by that point the calendar was in error by approximately two days.
- Nussbaum, Louis-Frédéric. (2005). "Semmei-reki" in Japan Encyclopedia, at p. 840.
- Orchiston, Wayne; Nakamura, Tsukao; Strom, Richard. (2011).  Highlighting the history of astronomy in the Asia-Pacific Region, p. 159.
- Needham, Joseph. (1959). Science and civilisation in China, Mathematics and the sciences of the heavens and the earth, Vol. 3, p. 391 note d.
- Japan, Monbushō. (1876). An outline history of Japanese education: prepared for the Philadelphia International Exhibition, 1876, p. 160.
- Charlotte von Verschuer (1985). Les relations officielles du Japon avec la Chine aux VIIIe et IXe siècles (Hachi-kyū-seiki no Nitchū kankei), pp. 243-245 n. 114. (French)