Onmyodo

Onmyodo, "the way of yin and yang," is the Japanese system of divination, cosmology and ritual that grew from Chinese natural philosophy imported into Japan and there developed into something distinctively its own. Its raw materials were Chinese: the interplay of yin and yang (Japanese on and yo), the five phases or elements (gogyo, wood, fire, earth, metal, water), the sexagenary calendar, and the arts of astrology, calendar-making and geomancy. Under the ritsuryo state these were institutionalised in a government office, the Onmyoryo (Bureau of Yin and Yang), whose officials, the onmyoji, handled the calendar, observed the heavens for omens, and advised on the timing and direction of the court's actions.

From this grew an elaborate practice of avoiding misfortune: directional taboos (katatagae, changing one's route to avoid an inauspicious direction) and days of ritual seclusion (monoimi) governed the lives of the Heian aristocracy, for whom the onmyoji's reading of lucky and unlucky was a constant concern. Its most legendary practitioner, Abe no Seimei (921-1005), became a figure of folklore, credited with commanding spirit-servants (shikigami) and remembered in shrines, theatre and, today, popular fiction and film.

Onmyodo was an office of state before it was anything else. The court established a Bureau of Yin and Yang, staffed by salaried officials responsible for the calendar, for astronomical observation, for timekeeping and for determining which days and directions were safe for the emperor and the aristocracy. Its practitioners were civil servants, and their work touched the daily conduct of the court continuously: journeys were rerouted, appointments deferred and buildings sited on their advice.

The most famous of them, Abe no Seimei, became a legendary figure within a century or two of his death and has remained one, appearing in tale collections, in theatre and in modern film and comics. The historical official is much harder to see behind the legend.

Hereditary control of the office consolidated in two families, one of them descended from Seimei, and the resulting lineage held authority over practitioners across the country into the early modern period, licensing them and taking a share of their fees.

The Meiji government abolished the whole apparatus in 1870, as part of the same programme of rationalisation that separated kami from buddhas. What had been a branch of government became, at a stroke, a private and somewhat disreputable practice.

It survives now in folk practice, in the almanac conventions of lucky and unlucky days that remain in ordinary Japanese use, and in an extensive popular culture that has made a courtier of the tenth century into a recurring hero.