Recent eras correspond to the reigns of emperors. Previous eras do not correspond to reigns of emperors but to what were decided to be `auspicious events'.

To convert a date from the Japanese era to a Western date add the number in the `Add' column to the Japanese year. So for example `shoowa 25' is 1950.

The Japanese government started using the Gregorian calendar in Meiji 6. So the day before January 1 of Meiji 6 was not December 31 of Meiji 5, but December 2 of Meiji 5.