Changes

Japan early took over  the [[Sexegenary cycle]] (''kanshi'' 干支) system from China.  Japan and China use completely different ''nengô'', but 1504 was the year of 甲子 throughout east Asia.  

Japan early took over  the [[Sexegenary cycle]] (''kanshi'' 干支) system from China.  Japan and China use completely different ''nengô'', but 1504 was the year of 甲子 throughout east Asia.  

The system appears as a way of indicating days in the earliest Chinese writings, the 13th-century BC Shang-period oracle bones, but around the 2nd century BC it came to be used also for years. Japan adopted this system in the earliest dates we have, a sword dated 辛亥, probably 471 from the reign of [[Emperoro Yuryaku|Emperoro Yûryaku]], and a mirror from Wakayama dated 癸未年, probably 443 or 503. Also, on the 7th-century administrative wooden tablets found in various capitals, the years are indicated using the cycle.

The system appears as a way of indicating days in the earliest Chinese writings, the 13th-century BC Shang-period oracle bones, but around the 2nd century BC it came to be used also for years. Japan adopted this system in the earliest dates we have, a sword dated 辛亥, probably 471 from the reign of [[Emperor Yuryaku|Emperor Yûryaku]], and a mirror from Wakayama dated 癸未年, probably 443 or 503. Also, on the 7th-century administrative wooden tablets found in various capitals, the years are indicated using the cycle.

In this system, two series of characters, the ten stems (''kan'' 干) and the twelve branches (''shi'' 支 ) are used cyclically. They can be combined into a series of sixty elements (see the article on the cycle), which may be used to indicate years.  甲子, the first element of the series, can indicate the years 904, 964, 1024, 1084, 1144, 1204, and all other years separated from these by a multiple of 60. 乙巳, the 42nd element in the series, can be 886, 946, 1006, 1066, 1126, 1186, 1246, etc.  It is also common to indicate a year using only the branch, or ''shi'', part of the cycle.  Thus 巳 occurs every twelve years, as 886, 898, 910, etc. As the branches have gotten animal names attached to them, the years expressed by branches are often translated using animal names. A 巳 year is a "Year of the Snake," for example. Note, however, that since the cyclic terms repeat, one needs some more information than just the cyclic name to completely identify the year.

In this system, two series of characters, the ten stems (''kan'' 干) and the twelve branches (''shi'' 支 ) are used cyclically. They can be combined into a series of sixty elements (see the article on the cycle), which may be used to indicate years.  甲子, the first element of the series, can indicate the years 904, 964, 1024, 1084, 1144, 1204, and all other years separated from these by a multiple of 60. 乙巳, the 42nd element in the series, can be 886, 946, 1006, 1066, 1126, 1186, 1246, etc.  It is also common to indicate a year using only the branch, or ''shi'', part of the cycle.  Thus 巳 occurs every twelve years, as 886, 898, 910, etc. As the branches have gotten animal names attached to them, the years expressed by branches are often translated using animal names. A 巳 year is a "Year of the Snake," for example. Note, however, that since the cyclic terms repeat, one needs some more information than just the cyclic name to completely identify the year.