japanese: First two hieroglyphs are name of emperor. In this case it is Shōwa (http://en.wikipedia.org/wiki/Hirohito). His reign started in 1926. So 54-th year of reign will be 1925+54 = 1979. This is a year of coin.

1925 instead of 1926 is used because 1926 is a not zero, but first year reigning.

Article about manual years calculations is still in progres. I hope I will finish it in nearest time.

Thank you for reply. You help me a lot today!!!

japanese: At this moment — no. I'm planning to implement this feature in nearest time.

This will be great! But, I want to write down correct year in my coins list now... Can you provide me calculation rules for Japanese dates? I'm not sure that I'm correctly understand how it should really to be.

There is Japanese coin with Arabic numbers. Is it possible to use Dates Calculator with such dates and how?