Kawara Shashinki-ten (河原写真機店) was a Japanese distributor based in Osaka, active from the early 1920s to the early 1940s. It advertised the Okaco, the Oko Six and the Letix at the beggining of the 1940s.
- Ars Camera. Advertisement by Kawara Shashinki-ten in September 1921. No page number.
- 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.