Sukuyō-dō 宿曜道 (Japanese Astrologers)

           An influential tradition and lineage of Japanese Buddhist astrologers (sukuyōshi 宿曜師) which originated in the late tenth century and vanished in the fourteenth century, existing alongside and often competing with the Onmyōdō 陰陽道. While recognized as a lineage, they did not possess sect-specific doctrines and often had differing views. Although sukuyō 宿曜 has been assumed to refer to the Xiuyao jing 宿曜經 (T 1299), that text was secondary to the tradition which drafted natal charts (horoscopes or sukuyō kanmon 宿曜勘文) primarily for aristocrats and predicted eclipses for the court using the Futian li 符天曆 calendar (compiled by Cao Shiwei 曹士蒍 between 780–783) and Duli yusi jing 都利聿斯經 (translated between 785–805), a method not provided in the Xiuyao jing. The horoscopes required advanced calendrical science to determine the positions of the nine planets 九曜 (sun, moon, five visible planets plus Indian pseudo-planets Rāhu 羅睺 and Ketu 計都) at any time in the past to detail influences such as astrological aspect (the angles of planets relative to one another) and the twelve places 十二位 or houses (Latin: domus), which are characteristically Hellenistic. For a list of extant horoscope specimens see Momo (1975). The sukuyōshi also provided ritual services to patrons to enhance or deflect astrological influences and maximize longevity, often based on individual horoscopes.

The Xiuyao jing was brought to Japan by Kūkai 空海 (774–835) in 806 and again by Ennin 圓仁 (794–864) in 847 and Enchin 圓珍 (814–891) in 858. The Taishō version of this text is an edited mainland version different from original Japanese manuscripts which Kakushō 覺勝 used for his authoritative version published in 1736 (for an extensive study see Yano 2013). Sukuyōdō most likely exclusively used the latter textual lineage. The Kōya Daishi go kōden 高野大師御廣傳 and Kōbō Daishi go den 弘法大師御傳 (Zoku gunshoruijū 續群書類從 8) record that calendar experts were unaware of Sunday and the related astrological calendar until Kūkai introduced it. The Hino'o kuketsu 檜尾口訣 (T 2465) by Jichie 實慧 (786–847) of Tōji, which records Kūkai's oral lectures, records instructions for intercalary months 閏月 and short months 小月 (29 day months) based on the Xiuyao jing (勘宿曜經取潤月之宿及小月之闕日分宿法). These two items indicate it was Kūkai who first introduced Amoghavajra's 不空 astrology to Japan. Ennin's biography the Jikaku Daishi den 慈覺大師傳 (Zoku gunshoruijū 8) likewise records him in 849 following it, showing its importance to early Taimitsu 台密.

Shū'ei 宗叡 (809–884) brought the Duli yusi jing in 865, though it is not extant. The Xin wu dai shi 新五代史 (fasc. 58) describes the Futian li as a 'lesser calendar' 小歷 which only initially circulated amongst commoners, but eventually merited being used at court for five years. It states its starting point is the year 660 (Xianqing 顯慶 5) with the start of the year 首 being yushui 雨水, which is necessary to understand Sukuyō horoscopes as they state the number of days elapsed since then (積日數). For example, the Sukuyō unmei kanmon 宿曜運命勘文, a horoscope for an individual born on lunar 12/25 in Ten'ei 天永 3 (1113) states that 165,428 days have elapsed: 165,428 ÷ 365 = 453; 660 + 453 = 1113. The Futian li is unique in being an unofficial calendar available to the masses in China who in the ninth century increasingly required it to compile horoscopes. It incorporates both Greek and Indian elements. Although the Futian li was available in Japan when the Nihonkoku kenzai sho mokuroku 日本國見在書目錄 was compiled by Fujiwara no Sukeyo 藤原佐世 (d. 897) in c.891 (listed as 唐七曜符天曆一 under the 天文家 heading), in 953 the monk Nichi'en 日延 (d.u.) at the request of the onmyōji 陰陽師 Kamo no Yasunori 賀茂保憲 (917–977) was ordered to fetch a new calendar, whereupon in the state of Wuyue吳越 he studied and retrieved a version of the Futian li, which he brought back in 957. Nichi'en was chosen for this role because he was disciple of Tendai monk Ninkan 仁觀 (d. 934), who had a background in calendrical science. The Futian li was used alongside the Senmyō reki 宣命曆 by calendar experts 曆道, whom the sukuyōshi debated with in particular with respect to eclipse predictions until the end of the Kamakura period 鎌倉時代 (1185–1333). The sukuyōshi participated in official calendar production from 995 when Ninsō 仁宗 was ordered to assist. This participation ended in 1038. Unlike official Chinese calendars, the Futian li was necessary for Buddhist astrology as it calculated the positions of Rāhu and Ketu. For details see Momo (1969), Yamashita (1990).

The origins of Sukuyōdō are traced back to a need for an accurate astrological schedule for Mikkyō 密教 rites (see comments on timing the maṇḍala in fasc. 4 of theDari jing shu 大日經疏T 1796) and related star worship. This led to the appearance of monks specializing in astrology, such as Ninkan, who in 926 set the date for a major rite (see Teishin kōki shō 貞信公記抄). Likewise in this century there were star worship rites for the Tennō 天皇, which required ascertaining his birth day 本命日and birth constellation 本命宿. In 961 for the Murakami Tennō 村上天皇 (926–967; r. 946–967) the monk Hōzō 法藏 (905–969) debated with Kamo no Yasunori over this, highlighting the early division between Sukuyōdō and Onmyōdō and increasing faith in star worship. Said rites along with horoscopes subsequently became widely done for the aristocracy from the late tenth century onward. There are many examples of sukuyōshi performing rites when eclipses occurred. Other rites were heavily Daoist in nature, such as those for the Big Dipper 北斗法 aimed at extending longevity 延命, which became prominent in the late Heian period.

Hōzō, who had also probably studied the Futian li, later on was designated as the first sukuyōshi. The earliest datable appearances of terms Sukuyōdō and sukuyōshi in journals of aristocrats are from the beginning to the mid-eleventh century (Toda 2007), though sukuyōdōhō 宿曜道法 appears in a citation of Hōzō's debate recorded in the Ono rui hishō 小野類祕鈔 by Kanshin 寬信 (1084–1153). The noun sukuyō, referring to astrologers, appears in Murasaki Shikibu's 紫式部 Tale of Genji 源氏物語(chap. 1 and 14) in the early eleventh century.

The late Kamakura-era Nichūreki 二中歷 (#13, ichi nōreki 一能歷) lists the following lineage of sukuyōshi: Hōzō 法藏, Rigen 利源(), Ninsō 仁宗, Ninso 仁祚, Nintō 仁統, Fusen 扶宣, Chūin 忠允, Ryōtan 良湛, Zōmyō 增命, Shōshō 證昭, Genso 彥祚, Nōsan 能算, Shōshō ()淸昭, Gōshun ()恆舜, Kokkū 國空, Songen 尊源, Kensen 賢暹, Kyōzō 慶增, Ryōyū 良祐, Myōsan 明算, Shinsan 深算, Nichikaku 日覺. It also lists the following rokumyōshi 祿命師 (specialists of Chinese luming 祿命 divination) with four in common: Nichi'en 日延, Fusen 扶宣, Ryōtan 良湛, Nōsan 能算, Chūshō 忠淸, and Kyōzō 慶增. Although several of these monks were from the Tōji 東寺 and Taimitsu 台密 lineages, from the mid-Heian period sukuyōshi primarily came from Kōfukuji 興福寺 (Hossō school 法相宗), the first known of which is Ninsō (b.945?). The journal of Fujiwara Sanesuke 藤原實資 (957–1046), the Shōyūki 小右記, reports in 982 (Tengen 天元 5) his monastic affiliation and him being ordered to compile an astrology report. Later two mainstream lineages emerged and remained active in the Kamakura period: the Chinryū 珍流 (variant: 珎流) and Sanryū 算流. Many such names are recorded in the Sonpi bunmyaku 尊卑分脈 compiled by Tōin Kinsada 洞院公定 (1340–1399) in 1376. In the Insei period 院政期, the two prominent sukuyōshi were Chinga 珍賀 and Kyōsan 慶算. By the Kamakura period Sukuyōdō had spread to the city of Kamakura and transitioned from primarily casting horoscopes to being ritual specialists (see Toda 2006, 2007). Other noted sukuyōshi include Shōichi 性一, Kenichi 兼一, En'ichi 圓一, Gien 義圓, and Ninken 任憲.

Sukuyōdō as an identifiable community vanished in the fourteenth century. The Shosaimon kojitsushō諸祭文故實抄 (final compilation in 1518 by Higashibōjō Kazunaga 東坊城和長 1460–1530) lists eight Sukuyōdō rites that were temporarily revised and carried out in the Ōei 應永 period (1399–1427) between 1394–1413. The final symbolic blow to the destruction of the tradition was when the Hokudokōrin-in 北斗降臨院 at Kiyomizudera 淸水寺 (built in 1165 by Chinga; see the Enjōji denki 園城寺傳記・九之十) burned down in 1417 as recorded in the Kanmon gyoki 看聞御記 (the journal of Fushiminomiya Sadafusa 伏見宮貞成 for the years 1416–1448).

In the twentieth century numerous popular works on sukuyō senseijutsu 宿曜占星術 were published in Japan, though these focus chiefly on the Xiuyao jing. Komine Yumiko 小峰有美子 (b. 1930) claims to have inherited a secret oral lineage from Iseki Tenkai 井關天海 representing the Sukuyōdō lineage (Komine 1982).


Komine, Yumiko 小峰有美子Sukuyō kyō nijūshichi suku senseihō.  宿曜經二十七宿占星法. Tokyo: Tōyō Shoin 東洋書院, 1982.

Momo Hiroyuki 桃裕行. “Nichi'en no Tenfu reki seirai.”  日延の天符曆齎來. In In Ritsuryō kokka to kizoku shakai.  律令國家と貴族社會, ed. Takeuchi Rizō 竹內理三, 395–420. Tokyo: Yoshikawa Kōbunkan 吉川弘文館, 1969.

Momo Hiroyuki 桃裕行. “Sukuyōdō to sukuyō kanmon.”  宿曜道と宿曜勘文. In Risshō shigaku.  立正史學 39 (1975): 1–20.

Murayama Shūichi 村山修一Nihon Onmyōdō shi sōsetsu.  日本陰陽道史總說. Tokyo: Hanawa Shobō 塙書房, 1981.

Toda Yusuke 戶田 雄介. “Kamakura bakufu no sukuyōshi: toku ni chinyo ni tsuite.”  鎌倉幕府の宿曜師 : 特に珍譽について. In Bukkyō Daigaku daigakuin kiyō.  佛教大學大學院紀要 35 (2007): 45–59.

Toda, Yusuke 戶田雄介. “Sukuyōdō no inseiki: Chinga to Kyōsan wo chūshin ni.”  宿曜道の院政期 : 珍賀と慶算を中心に. In Bukkyō Daigaku daigakuin kiyō.  佛教大學大學院紀要 34 (2006): 27–40.

Toda Yusuke 戶田雄介. “Sukuyōdō saiki ni tsuite no ichi kōsatsu: hokuto hon haiku to hokuto hō.”  宿曜道祭祀についての一考察 : 北斗本拜供と北斗法. In Bukkyō Daigaku daigakuin kiyō.  佛教大學大學院紀要 36 (2008): 33–48.

Yano, Michio 矢野道雄Mikkyō senseijutsu.  密教占星術. Tokyo: Toyoshoin, 2013.

Yamashita Katsuaki 山下克明. “Heian jidai ni okeru mikkyō seishinku no seiritsu to dōkyō.”  平安時代における密教星辰供の成立と道教. In Nihonshi kenkyū.  日本史硏究 312 (1988): 37–61.

Yamashita Katsuaki 山下克明Heian jidai no shūkyō bunka to onyōdō.  平安時代の宗教文化と陰陽道. Iwata Shoin 岩田書院, 1996.

Yamashita Katsuaki 山下克明. “Sukuyōdō no keisei to tenkai.”  宿曜道の形成と展開. In Kōki sekkan jidaishi no kenkyū.  後期攝關時代史の硏究, 481–527. Tokyo: Yoshikawa Kōbunkan 吉川弘文館, 1990. 日本國見在書目錄

Nihonkoku genzai sho mokuroku: The oldest extant catalog of Chinese texts 漢籍 in Japan, listing 1579 works. Compiled by Fujiwara no Sukeyo 藤原佐世 (d. 897) in c.891. One fasc. It follows the format of the Jingji zhi.  經籍志 of the Sui shu.  隋書, listing numerous texts not found in the Tang shu.  唐書, making it an important historical source. Also called Nihon genzai sho mokuroku.  日本見在書目錄Honchō genzai sho mokuroku.  本朝見在書目錄Sukeyo roku.  佐世錄Fujiwara no sukeyo chūmon.  藤原佐世注文. The oldest version is at Murōji 室生寺.

Yajima Genryō 矢嶋玄亮Nihonkoku genzai sho mokuroku: shūshō to kenkyū.  日本國見在書目錄 : 集證と硏究. Tokyo: Kyuko Shoin 汲古書院, 1984.

[Jeffrey Kotyk; source(s): Nipponica, Toda, Yano]