Sankei Shōkai (三恵商会) was a Japanese company active in 1939. It sold an accessory reflex viewfinder, offered for ¥10 in a December 1939 advertisement. The words DISTANCE METER are inscribed at the front, above the focusing lens, but it is unclear if this is the official name. The advertisement refers to the device as a "range and view-finder" (ファインダー距離計), and does not give any particular name. The device is somewhat similar to the Kuhn Flexameter or to the DeMornay-Budd Reflex Viewfinder. It does not couple to the camera lens, and the user has to manually transfer the distance reading obtained to the camera. The advertisement says that the finder contains two optical lenses and a prism, and that the resulting image is not inverted at all.
- Advertisement on p.11 of Nihon Shashin Kōgyō Tsūshin, December 15, 1939, reproduced on p.45 of Hyaku-gō goto jūkai no kiroku.
- Nihon Shashin Kōgyō Tsūshin (日本写真興業通信). Hyaku-gō goto jūkai no kiroku (百号ごと十回の記録, Ten records, every hundred issues). Tokyo: Nihon Shashin Kōgyō Tsūshin Sha (日本写真興業通信社), 1967. No ISBN number. Advertisement on p.53, corresponding to p.19 of the December 15, 1939 issue.