Reportedly found by a Japanese court in October 2004 to have exported, without Japanese government authorization, two jet mill grinding machines (which reportedly can be used to grind solid fuel into fine powder for use in missiles ) to Iran, allegedly to a military goods company and to a rocket science laboratory at a university, in May 1999 and November 2000; reportedly ordered to pay a fine of 15 million yen; five of its employees were arrested on June 12, 2003 by Japanese police on charges of exporting equipment to Iran that could be used in the production of missiles; in October 2004, 70-year-old Seishin president Haruhiko Ueda was reportedly sentenced to a 30-month jail term suspended for five years, while 42-year-old former Seishin employee Akira Kamiya was reportedly sentenced to an 18-month jail term suspended for three years; Seishin was suspected of selling the jet mills knowing they would be used for missile development; repeatedly raided by Japanese police since December 2002.

Suspected of supplying a jet mill to North Korea in 1994 by selling it to a company with close ties to the pro-Pyongyang General Association of Korean Residents in Japan (Chongryon); reportedly sold electronic scales to North Korea in 1994 that can be used in the production of biological and chemical weapons; reportedly made a false declaration to the customs authorities at the time, stating that the exported products were not items covered by the MTCR; reportedly exported a jet mill in 1987 to the former Soviet Union and another to Iran.

Established in 1968 as a manufacturer of grinding and pulverizing equipment/machinery and powder characteristic measuring equipment.