Moonwise

Japanese Lunar Year, Heisei 16-17 (2004-05)
January 2004 - February 2005

The Gregorian Calendar has been in official use in Japan since 1873 CE, and most festivals and all secular holidays now follow it, but the Japanese Lunar Calendar continues to be published, and determines the date of some festivals, especially the Moon-viewing festival of Jugoya or Tsukimi. Since 1798 CE, astronomical predictions have been used to determine the date of the new month: these now begin with the day of the dark moon conjunction, with the day being midnight to midnight, Tokyo Time (UT+9 hours). The calendar is thus very similar to its ancestor, the Chinese Lunar Calendar, and differs from it only when the hour difference between Beijing and Tokyo matters. The tropical zodiac, related to the equinoxes and solstices, is used. However, as in China, the zodiac is split into 24 solar terms, each of fifteen degrees, with alternating major and minor terms. The major terms correspond to the start of a western sunsign, and the minor ones are 15° through each sign. The terms are dated as the Tokyo Time day on which they fall.

There are twelve numbered months with 29 or 30 days. The month containing Touji, the northern winter solstice solar term day, is always the eleventh month; every two or three years an extra month is added so that this continues to be the case. If an extra month is needed to keep the following Touji in the eleventh month, at least one month between the Touji days will not contain a major solar term day: the first of these months is made the extra one. It takes on the number of the month before: so that for instance it might be the second fifth month.

The years of the emperor’s reign are shown, preceded by the era name. Year one of a new era starts at the beginning of a new reign, backdated to 1 January.

updated 12th Lunar Month / January 2004