6

After a quick education I learned to read the Emperor names

and the numbers:

Armed with these characters and a few other bits and pieces, I was able to

attack the patents and put them in chronological order in this book.

Beginning in the late 1940s Japanese patents include the number in Western

numerals with each number preceded by the Emperor year. These are the

reigns of Emperor Hirohito and Emperor Akhito; also know as Shôwa and

Heisei eras. To convert the numbers to Western years is simple:

Hirohito (Shôwa era) reign was 1926-1989. To convert Emperor year

to Western Year add 25 (Coronation was 1928)

Akhito (Heisei era) reign began in 1989. To convert the year of reign

to Western Year add 88 (e.g. 3 + 88 = 1991)