Tsukimi (Moon Viewing)

Because jugoya is fixed in the lunisolar calendar, its Gregorian date changes each year, falling between about mid-September and early October; the National Astronomical Observatory of Japan publishes it annually. The astronomical full moon does not always coincide with jugoya and can be a day or two later.

Japan also has a second moon-viewing night that China does not: jusan'ya, the thirteenth night of the ninth month, about a month after jugoya. It is called kuri meigetsu or mame meigetsu, 'chestnut moon' or 'bean moon', after the offerings of the season. Viewing only one of the two moons, katamitsuki, was traditionally considered unlucky.

Moon-viewing on the mid-autumn night came from Tang China and took hold at the Heian court in the ninth and tenth centuries. Aristocrats held banquets in their gardens and on boats on ponds, admiring the moon in the sky and its reflection in the water and in their sake cups while composing waka poems. The moon has been one of the great seasonal subjects of Japanese poetry ever since, from the Kokinshu to the haiku of Matsuo Basho.

Among farmers the full moon of the eighth month was a thanksgiving for the harvest, especially of taro, which was offered on the night; hence the name imo meigetsu, 'taro moon'. In the Edo period both strands merged into the family custom known today, with dumplings made from newly harvested rice.

The classic tsukimi display stands where the moon can be seen: a stack of white rice dumplings on a small wooden tray, sprigs of susuki (Japanese silver grass) and seasonal produce such as taro, chestnuts, persimmons and grapes. Fifteen dumplings are placed for jugoya and thirteen for jusan'ya. Susuki stands in for rice ears, which are not yet harvested, and its sharp edges were thought to keep evil away; it is sometimes hung under the eaves after the night for protection.

In Kansai, tsukimi dango are often oval and wrapped in sweet bean paste, in the shape of a taro. The name tsukimi also appears on menus year-round: tsukimi soba and tsukimi udon are topped with a raw egg whose yolk resembles the moon.

Where Europeans see a face in the moon, Japanese tradition sees a rabbit pounding rice cakes with a mallet. The image comes from a Buddhist Jataka tale told in the Konjaku Monogatari: a rabbit, having nothing else to offer a hungry old man, threw itself into a fire as food; the old man, in truth a deity, placed the rabbit on the moon in recognition of its selflessness. The Chinese version has the rabbit pounding the elixir of immortality; in Japan the mortar became one for mochi, a pun often linked with mochizuki, 'full moon'.

Several historic sites were designed with the moon in mind and hold moon-viewing evenings around jugoya.