The Oko Six is a horizontal folder, whose body and struts are copied from the Ikonta B. There is an advance key at the top right, strap lugs on both ends of the top plate, a folding optical finder in the middle, a body release on the right and a folding bed release button on the left. All these features are copied from the Ikonta too. The back is hinged to the right and the film advance is certainly controlled by red window.
The shutter gives 1–350 speeds and it is certainly called "Precision". In the advertising pictures, the word PRECISION is faintly readable at the bottom of the shutter plate.
The Oko Six was advertised in August 1941 by the distributor Kawara Shashinki-ten. Two versions were offered, with f/4.5 or f/3.5 lens, respectively for ¥110 and ¥135. In this advertisement, the lens is called Oko Anastigmat (オーコーアナスチグマット) and is described as a Tessar type with four elements.
The camera was advertised in January 1942 by the company Sankō Shōkai, with the same advertising picture. In this advertisement, the Oko Six I has a Sanko Anastigmat 75/4.5 lens (¥123) and the Oko Six II has an Okor Anastigmat 75/3.5 lens (¥147, case ¥8.59 extra). The Okor lens is again described as having four elements. This lens was probably made by Ōki itself.
The camera is not listed in the official list of set prices compiled in October 1940 and published in January 1941. It was thus not yet produced at the time.
No surviving example of the Oko Six has been observed so far.
- Dates: advertisements and articles listed in Kokusan kamera no rekishi, p. 334.
- In the advertisements, the shutter name is written プレジョン (purejon) in katakana but this is surely a typo for プレシジョン (pureshijon or Precision).
- Advertisement published in Asahi Camera, reproduced in Kokusan kamera no rekishi, p. 61.
- Advertisement published in Hōdō Shashin, reproduced in Kokusan kamera no rekishi, p. 61.
- This name in roman letters is tentatively inferred from the katakana オーコール printed in the advertisement; the actual roman form may differ.
- "Kokusan shashinki no kōtei kakaku".
- 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. Item 33. (See also the advertisement for item 35.)
- "Kokusan shashinki no kōtei kakaku" (国産写真機の公定価格, Set prices of the Japanese cameras), listing Japanese camera production as of October 25, 1940 and setting the retail prices from December 10, 1940. Published in Asahi Camera January 1941 and reproduced in 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. Pp.108—9. The camera does not appear in this document.
The Oko Six is not listed in Sugiyama.