Nothing is known about this japanese professionnal system...
Apparently it was a small CAD/CAM system.
We need more info about this computer ! If you designed, used, or have more info about this system,
please send us pictures or anything you might find useful.
Please consider donating your old computer / videogame system to Old-Computers.com or one of our partners from anywhere in the world (Europe, America, Asia, etc.).
http://www2u.biglobe.ne.jp/~n-fuji/seiko.pdf
If I believe this document on the Japanese website, the Seiko 9500 was launched in 1981 and the Seiko 9100 in 1983.