Thank you Peter for all the information and history on your instrument. I enjoy seeing how instruments have been reinvented.

Yes, you are right, Lexie. From the article in the German wikipedia article I got the information, that the inventor of the instrument, Gorō Morita, had the chance to study musical instruments in Europe and the US from 1906 to 1908 and then built this instrument in Nagoya, Japan and sold these instruments in 1912. I don't know whether he saw a zither or mountain dulcimer during his travels.
The instrument is based on the Japanes two-string zither "Nigenkin" (also called "yakumo goto") - and actually the levers of a mechanical typewriter.

There's more information here:

http://taishokotoproject.com

The site is in Japanese, but there is one link to a pdf-file called "Introduction of the first Taisho-koto". There is information in English and Japanese in that booklet.

Very interesting, I think we can find zitter type instruments all around the world.

The Taisho Koto is a zither-related instrument with frets and typewriter-style levers. It was developped in the early 20th century and sold first in 1912, the year of the Japanese emperor Taisho - hence the name. Other names are: Taishokoto, Taishogoto, Nagoya-Harp, Nardan-Harp. In Japanese, Taisho Koto is spelled like this: 大正琴.
I uploaded this original photo to Wiki Commons also, so don't wonder when you find it there. It's my instrument. I bought it second-hand from Japan via ebay.