- OSK Co., Ltd.
- OTSUKA CORPORATION's software research and development company. Provides management systems and collaborative software (such as ERP packages and groupware, respectively) to cover a wide range of specialized fields, including CAD and web technologies such as Java. Established in 1984.
- NetWorld Corporation
- Provides comprehensive software, hardware, intranet and security products for the construction and expansion of computer networks. Has a wide range of product knowledge which it draws upon to develop solutions based on the particular needs of its clients. Also provides intermediary services between manufacturers and system integrators. Established in 1990.
Service and Support
- Alpha Techno Co., Ltd.
- Provides emergency computer rescue services for corporate and individual clients. Coordinates multi-vendor efforts consisting of pick-up, repair and return of computers it is asked to fix. Services are available on an ad hoc basis. Established in 1996.
- Alpha Net Co., Ltd.
- Advanced network service and support specialists with an extremely high level of technological capabilities and expertise. Offers 24/7 network support and comprehensive services for planning, design, construction and operation of corporate information systems. Also out-sources system engineers. Established in 1997.
- Otsuka Auto Service Co., Ltd.
- Sells new and used automobiles and accident insurance. Also offers automobile maintenance and repair services. Established in 1987.