Traditional Chinese lunisolar calendar

Traditional Chinese society used a lunisolar calendar. For the lunar calendar part, one year consists of 12 months. A month (yue 月) is the time from one new moon to the next. These synodic months are about 29+17⁄32 days long. Around every three years, there will be an additional leap month. Days (ri 日) in a mouth are numbered in sequence from 1 to 29 (or 30). The first day of the month is called chuyi 初一, which means “first one.” The second day is called chu’er 初二, the third day is 初三 chusan, and so on until the tenth day, chushi 初十. For the lunar calendar part, one year consists of 4 seasons. At the same time, there are 24 jieqi 節氣 [solar term] (Lichun 立春 [Beginning of Spring], Yushui 雨水 [Rain Water], Jingzhe 驚蟄 [Awakening of Insects], Chunfen 春分 [Spring Equinox], Qingming 清明 [Pure Brightness], Guyu 谷雨 [Grain Rain], Lixia 立夏 [Beginning of Summer], Xiaoman 小滿 [Grain Buds], Mangzhong 芒種 [Grain in Ear], Xiazhi 夏至 [Summer Solstice], Xiaoshu 小暑 [Minor Heat], Dashu 大暑 [Major Heat], Liqiu 立秋 [Beginning of Autumn], Chushu 處暑 [End of Heat], Bailu 白露 [White Dew], Qiufen 秋分 [Autumn Equinox], Hanlu 寒露 [Cold Dew], Shuangjiang 霜降 [Frost’s Descent], Lidong 立冬 [Beginning of Winter], Xiaoxue 小雪 [Minor Snow], Daxue 大雪 [Major Snow], Dongzhi 冬至 [Winter Solstice], Xiaohan 小寒 [Minor Cold], Dahan 大寒 [Major Cold]), and each of them matches a particular astronomical event or signifies some natural phenomenon and stay synchronized with the seasons. Each season is also evenly divided into three periods prefixed by meng- 孟 [the first], zhong- 仲 [the second], and ji-季 [the last], with each period lasting for two solar terms which is roughly the same amount of one month. So, jichun 季春 as mentioned later in the text is the third period of spring that lasts from the solar term Qingming 清明 up until Lixia 立夏, which is also roughly in the third month of the year.