At least three Japanese camera-related companies were called Sankō.
In 1943, a company called Sankō-sha (三光社) and based in Tokyo, Asakusa offered rangefinder conversions for the Gelto, Arsen, Picny, Boltax, Roico and Molby. It was also mentioned in the April 1943 government inquiry as the distributor of the Cyclon, a 3×4cm camera with perhaps a focal-plane shutter.
Between 1951 and 1954, K.K. Sankō (㈱三光), based in Tokyo, Taito made or sold the Baby Suzuka 3×4 camera. A company called Sankō K.K. (三光㈱) exists today (2007), and currently makes chemical products. It was founded as Sankō Shōkai (三光商会) in 1946 and became Sankō K.K. in 1949, so it might be the same company.
The relationship between all these companies is unknown.
- Its address in 1942 was Tōkyō Kyōbashi-ku Ginza 5–4 Tsuchida Building (東京・京橋区銀座五ノ四ツチダビル). Source: advertisement reproduced in Kokusan kamera no rekishi, p.61.
- Its address in 1943 was Tōkyō-shi Asakusa-ku Asakusa-bashi 2-chōme 4-banchi (東京市浅草区浅草橋二丁目四番地). Source: advertisements reproduced in Kokusan kamera no rekishi, pp.111–2.
- "Kokusan shashinki no genjōchōsa" ("Inquiry into Japanese cameras"), item 162.
- Its address in 1952 was Tōkyō-to Taitō-ku Okachi-machi 1–58 (東京都台東区御徒町1~58). Source: advertisements reproduced in Kokusan kamera no rekishi, p.142.
- Asahi Camera (アサヒカメラ) editorial staff. Shōwa 10–40nen kōkoku ni miru kokusan kamera no rekishi (昭和10–40年広告にみる国産カメラの歴史, Japanese camera history as seen in advertisements, 1935–1965). Tokyo: Asahi Shinbunsha, 1994. ISBN 4-02-330312-7.
- "Kokusan shashinki no genjōchōsa" (国産写真機ノ現状調査, Inquiry into Japanese cameras), listing Japanese camera production as of April 1943. Reproduced in Supuringu kamera de ikou: Zen 69 kishu no shōkai to tsukaikata (スプリングカメラでいこう: 全69機種の紹介と使い方, Let's try spring cameras: Presentation and use of 69 machines). Tokyo: Shashinkogyo Syuppan-sha, 2004. ISBN 4-87956-072-3. Pp.180–7.
- Official website of today's Sankō (perhaps unrelated)