The company's main products were a word processor, Ichitaro ("JohnnyOne"), a Japanese input method, ATOK.

Its most recent business has focused on Java and XML-themed technology development.

[2] JustSystems was founded in 1979 by Hatsuko and Kazunori Ukigawa, and was incorporated in June 1981.

Early in the company's history, it created one of the first computer input methods for Japanese users, creating compatibility between QWERTY keyboards and Kanji characters.

Later that year, Kazunori and Hatsuko Ukigawa resigned from the company.