When is the leap sixth month?
17th century: 1653 (Gui Si year), 1664 (Jia Shen year), 1683 (Gui Hai year)18th century: 1702 (Ren Wu year), 1721 (Xin Chou year), 1740 (Geng Shen year), 1759 (Ji Mao year), 1778 (Wu Xu year), 1797 (Ding Si year)
19th century: 1805 (Yi Chou year), 1816 (Bing Zi year), 1835 (Yi Wei year), 1873 (Gui You year), 1892 (Ren Chen year)
20th century: 1911 (Xin Hai year), 1930 (Geng Wu year), 1941 (Xin Si year), 1960 (Geng Zi year), 1979 (Ji Wei year), 1987 (Ding Mao year)
21st century: 2017 (Ding You year), 2025 (Yi Si year), 2036 (Bing Chen year), 2055 (Yi Hai year), 2074 (Jia Wu year), 2093 (Gui Chou year)
22nd century: 2112 (Ren Shen year), 2131 (Xin Mao year), 2150 (Geng Xu year), 2161 (Xin You year), 2169 (Ji Si year), 2180 (Geng Chen year), 2188 (Wu Zi year), 2199 (Ji Hai year)
23rd century: 2207 (Ding Wei year), 2245 (Yi You year), 2256 (Bing Shen year), 2275 (Yi Mao year), 2283 (Gui Hai year), 2294 (Jia Xu year)
24th century: 2302 (Ren Wu year), 2313 (Gui Si year), 2332 (Ren Zi year), 2351 (Xin Wei year), 2370 (Geng Yin year), 2389 (Ji You year), 2397 (Ding Si year)
25th century: 2408 (Wu Chen year), 2427 (Ding Hai year), 2465 (Yi Chou year), 2484 (Jia Shen year)
26th century: 2503 (Gui Mao year), 2522 (Ren Xu year), 2533 (Gui You year), 2552 (Ren Chen year), 2571 (Xin Hai year), 2579 (Ji Wei year)
27th century: 2609 (Ji Chou year), 2617 (Ding You year), 2628 (Wu Shen year), 2647 (Ding Mao year), 2666 (Bing Xu year), 2685 (Yi Si year)
28th century: 2704 (Jia Zi year), 2723 (Gui Wei year), 2742 (Ren Yin year), 2753 (Gui Chou year), 2761 (Xin You year), 2772 (Ren Shen year), 2780 (Geng Chen year), 2791 (Xin Mao year), 2799 (Ji Hai year)
29th century: 2810 (Geng Xu year), 2837 (Ding Chou year), 2848 (Wu Zi year), 2867 (Ding Wei year), 2875 (Yi Mao year), 2886 (Bing Yin year), 2894 (Ji Xu year)
30th century: 2905 (Yi You year), 2924 (Jia Chen year), 2943 (Gui Hai year), 2962 (Xin Wu year), 2981 (Xin Chou year), 2989 (Ji You year), 3000 (Geng Shen year)
Is the leap sixth month a common leap month?
(1) The leap fifth month is the most common among all leap months, and the leap fourth month and the leap sixth month are also common leap months.(2) The frequency of the leap seventh month is second only to the leap fourth, fifth, and sixth months, so it can be called a relatively common leap month.
(3) The leap second, third, and eighth months appear with a frequency that is second only to the leap seventh month, so these three leap months can be called medium-frequency leap months.
(4) The frequency of the leap ninth and tenth months is second only to the leap second, third, and eighth months, and the years when the leap ninth and tenth months occur are fewer, so these two leap months can be called relatively rare leap months.
(5) The frequency of the leap winter month is second only to the leap ninth and tenth months, so it can be called a very rare leap month.
(6) The leap first and twelfth months not only have the lowest frequency of occurrence, but also the leap first month's first day can be called the leap Spring Festival, and the last day of the leap twelfth month can be called the leap New Year's Eve, so these two leap months can be called special leap months.
(7) It should be noted that the above rules are closely related to the positions of the perihelion and aphelion. Under the fixed solar term conditions, leap months near the perihelion are rare (and must be short months), while those near the aphelion are common. However, since the perihelion and aphelion are constantly moving, the above six rules cannot apply to future long-term lunar calendars (or to ancient lunar calendars calculated according to current rules).
