Toyo Seiko was perhaps a Japanese company. The engraving TOYO SEIKO Co. is found on the top housing of the Rolex 35 III, a 35mm viewfinder camera. The Rolex TLR is attributed to Toyo Seiko by Sugiyama, probably because of the name similarity, but this is unconfirmed.
The actual Japanese name is perhaps Tōyō Seikō (東洋精光), meaning "Oriental Precision Optics". One source says the company is the same as Tōyō Seiki Kōgaku (Toyo Seiko would be an abbreviation). This is unconfirmed but a number of coincidences might indicate that it was the case:
- the Rolex 35 III has a Luna lens, the same name as the Luna shutter made by Tōyō Seiki Kōgaku;
- Tōyō Seiki Kōgaku certainly became Cosmo Camera Seisakusho in 1955 and made a name variant of the Cosmo 35 called Rolex 35 too.
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover).
- Sugiyama, Kōichi (杉山浩一); Naoi, Hiroaki (直井浩明); Bullock, John R. The Collector's Guide to Japanese Cameras. 国産カメラ図鑑 (Kokusan kamera zukan). Tokyo: Asahi Sonorama, 1985. ISBN 4-257-03187-5.