SamuraiWiki:About dates

Use of Dates on the SamuraiWiki

Until 1873, Japan used a lunar calendar, either the Chinese calendar or a close relative. The dates in this calendar are about three to seven weeks after the corresponding Western (Gregorian) date, depending on the year. Almost all source material uses this calendar for events in Japan before 1873, as do Japanese historians. Therefore all dates, unless otherwise noted, are the Japanese equivalent (the lunar calendar). However, the Western date will also generally be listed for events taking place between Commodore Perry's arrival in Japan in 1853 until the Japanese calendar was changed to the Western Gregorian calendar in 1873, or in the years before this if it is pertinent to the article in question. It will also be used for events prior to this when applicable, namely when Westerners were involved in the events of Japanese history during the Sengoku and early Edo period, or for historical events that are covered in English treatments of Japanese history (For example, the battle of Nagashino, the battle of Sekigahara, etc.) When the Western date is also applicable, it will be noted in various ways.

Article "Data" Headings

Dates listed in the data sections at the top of the articles which benefit from the notation of the Western dates are seen as follows:

• Birth: 1848/5/20 (6/20/1848)

This indicates that the person in question was born on the Japanese date of 5/20 in the year 1848, which corresponds to the Western date of June 20th of the same year.

In-Text Format

The standard for date listings in text are to write out the day, month, and year:

• The 20th day of the 5th month (of 1848)

Depending on context or flow of the text, 1848/5/20 or 5/20/1848 are also acceptable. Unless there is a second date in parenthesis, the dates listed are understood to be the Japanese equivalent.

In-Text Examples

Examples of the Japanese calendar followed by the Western calendar are as follows:

• 1867/6/14 (7/15/1867)
• The 14th day of the sixth month (July 15th)
• The 14th day of the sixth month, 1867 (July 15th, 1867)
• The 14th day of the sixth month of the third year of Keio (1867) (July 15th, 1867)
• The 14th day of the sixth month of Keio 3 (1867) (July 15th, 1867)
• The 14th day of the sixth month, 1867 (7/15/1867)

And so on. In all cases, the Japanese lunar calendar comes first, followed by the Western date.

Intercalary Dates

In the Chinese-type lunar calendar, about every two years and eight months an extra month, i.e. a "leap month" or intercalary month, is inserted to keep the lunar calendar from becoming too separated from the seasons. This extra month is indicated on the SamuraiWiki by "int." For example, the third month of 1599 (1599/3) was followed by the intercalary third month (1599/int. 3), followed by the fourth month (1599/4).