Old Japanese Era Conversion

This article is written to complement the Japanese era conversion chart, which covers the years from the beginning of the Meiji period in 1868.

It lists the years of the Edo period (1615--1868) and also the preceding Azuchi-Momoyama period (1573--1615), as well as the later years of the Muromachi period (1394--1573), beginning with the reign of 104th Emperor Go-Kashiwabara, which coincides with the start of the 16th century.

For the eras from 645 to 1501, see Wikipedia.

John F.This looks a highly dubious project to me. First, there is a very important difference between this table and the table for the Meiji, Taisho, Showa eras etc. They follow the Gregorian calendar (for Meiji, only since 1873), so each Japanese year has the same span as ours. But prior to 1873 the lunar calendar was in operation and so portions of the Japanese year will be in two Gregorian years The size of the portions vary every year, and so does the number of months in each year. This shows up most often in go in the case of the Castle Games when they were held on lunar XI 17. So in Horeki 8, 9 and 10, in Gregorian terms the Castle games were NOT held in 1758, 1759 and 1760, but in 1758, 1760 and 1760.

    Similarly, Jowa (by one account) died in Koka 4, and using the table here people would assume he died in 1847. But he died in 1848 as his death date was lunar XII 20, corresponding to January of the following Gregorian year.
    And of course even within the lunar system the same year can have two different era names. Whichever way you present it, all this needs to be explained.
    As to the use of Edo X and Muromachi Y, I have never seen this system used,  anywhere - never mind in go - ever. And it is hardly likely to be of use to anyone anyway because there is widespread disagreement about when these periods start and end. For both Edo and Muromachi there are at last five common definitions, so that Edo is regarded as starting in 1600, 1603 or 1615 and ending in 1867 or 1868. The choice depends on whether one is talking about art or history or archaeology or whatever other field. Within each field no-one uses things like Edo 21.
   Surely the most useful procedure is to point users to a site that does full conversion (or use the GoGoD95 program).