24 solar terms - 24 solar terms

Japanese: 二十四節気 - にじゅうしせっき

A general term for the 12 mid-season periods and 12 seasonal periods established in the Chinese and Japanese lunisolar calendar to align calendar dates with the seasons. It is also called the 24 seasonal periods or simply the seasonal periods. The seasonal periods and seasonal periods are arranged alternately, and there are two methods for determining them: the Heiki method and the Teiiki method. The Heiki method determines the number of days between the seasonal periods and the seasonal periods by dividing the length of a year by 24, which is 365.25 days, and fixes the winter solstice to a specific month (November), and establishes the principle that the seasonal period is fixed for each month. Since a lunisolar calendar month (about 29.5 days) is slightly shorter than the interval between seasonal periods (about 30.4 days), there are months that do not include seasonal periods. If this month is designated as a leap month, then the time to place the leap month in the year is determined. This method of determining the leap month is called the mid-year leap month method. The fixed-qi method divides the ecliptic into 24 equal parts at 15° intervals, and determines the dates of the solar terms and mid-season periods when the sun passes each equinox. For example, when the sun passes the 0° point of the ecliptic longitude, it is called the vernal equinox, and is the mid-season period of February, and when it passes the 15° point, it is called the Qingming and March solar terms. However, the movement of the sun is not constant. For example, it takes 31 days and 11 hours to travel 30° on the ecliptic from the summer solstice to the great heat, but it takes only 29 days and 10 hours to travel 30° from the winter solstice to the great cold. The latter is shorter than one month in the lunisolar calendar, and there are two or three months a year that do not include a mid-season period, and there are also months that include two mid-season periods before and after that, so the intercalary method cannot be applied, and the intercalary method becomes complicated. The fixed-qi method has been adopted in China since the Shixian calendar of the Qing dynasty, and in Japan since the Tenpo calendar of 1844 (the current so-called lunar calendar is also based on the fixed-qi method). In addition to the 24 solar terms, there are specific days or periods that are set as seasonal guidelines called miscellaneous periods. The method of dividing the solar terms into thirds to create 72 periods was also introduced to Japan from China and was revised to suit the Japanese situation, but the only one that is still observed today is Hangesho, which occurs at the beginning of July.
→ Related topics Seasons | Summer solstice | Little cold | Great cold | Chinese calendar | Winter | Beginning of summer | Beginning of autumn | Beginning of spring | Beginning of winter | Calendar notes

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

中国，日本の太陰太陽暦で暦日と季節を合わせるために設けた，12個の中気と12個の節気の総称で，二十四気または単に節気ともいう。節気，中気を交互に配列するが，その決め方に平気法と定気法がある。平気法は１年の長さを365.25日とすると，これを24で割った15.21875日が節気から中気までの日数と定める方法で，冬至点は特定の月（11月）に固定し，各月に中気を固定するという原則を定めた。太陰太陽暦の１ヵ月（約29.5日）は中気から中気までの間隔（約30.4日）より少し短いので中気を含まない月が生ずる。そこでこの月を閏(うるう)月とすれば１年の中でどこに閏を置くかが決定される。この閏月の決定法を歳中置閏(さいちゅうちじゅん)法という。　定気法は黄道を15°おきに24等分し，太陽が各分点を通過する時点で節気，中気の日付を決める方法で，たとえば太陽が黄経０°の点を通過するときを春分と呼び，２月の中気とし，15°の点では清明，３月の節気とする。しかし太陽の動きは一定でなく，たとえば夏至から大暑までの黄道上30°をいくのに31日11時間かかるのに，冬至から大寒までの30°をいくのに29日10時間しかかからない。後者は太陰太陽暦の１ヵ月より短く，中気を含まない月が１年に２度，３度と生じたり，その前後では二つの中気を含む月もでき，歳中置閏法は適用できず，置閏法は複雑となる。中国では清代の時憲暦以降，日本では1844年の天保暦以降，定気法を採用（現在のいわゆる旧暦も定気法）。　なお，二十四節気以外に季節の目安として設けられた特定の日や期間を雑節という。また節気の間をさらに３等分し七十二候とする方法も中国から日本に伝えられ，日本の実情に合わせて修正されたりしたが，現在でも生きているのは７月初めの半夏生(はんげしょう)のみである。
→関連項目季節｜夏至｜小寒｜大寒｜中国暦｜冬｜立夏｜立秋｜立春｜立冬｜暦注

出典　株式会社平凡社百科事典マイペディアについて　情報

<<: 27th year thesis - 27th year thesis

>>: Twenty-four Filial Piety