NEC M-System keyboards History

By Xah Lee. Date: 2014-02-28. Last updated: 2020-05-25.

In 1983, NEC 日本電気 came out with a new keyboard and new Japanese input system, called M-system (M式), designed by Dr. Masasuke Morita at NEC.

M-system is 2 things:

A physical keyboard design that has 4 or more thumb keys, and symmeric (typically have dedicated sections for left hand and hand).
A efficient Japanese input system. It's a romanji input system. (you type English Letter then convert to kata (Japanese alphabet)) The English letter arrangement is optimized for kana.

Over the years, there are several M-system keyboard designs. Here's a list of them.

Reference

[【NEC】 Keyboard based on new input system (M system) 2013-01-21 By Information Processing Society Of Japan. At http://museum.ipsj.or.jp/en/computer/word/0027.html ]

2020-05-06 Thanks to NimShiko [https://medium.com/@elderiomeersky] for correction.