The Banzaikin (バンザイキン) is a Japanese conversion kit allowing to use 35mm film in 6×6 TLR cameras, made around 1944 by an unknown company. The name "Banzaikin" was obviously inspired by the Rolleikin. The device was suited for the Rolleicord, Lyra Flex, Minoltaflex and all other Japanese TLR cameras of the time; it was also available on order for the "Automat" models: Rolleiflex Automat and Minoltaflex Automat.
The Banzaikin was distributed by Kōgasō, with Banno Bōeki, Ōmiya Shashin-yōhin and Kinjō Shōkai as authorized dealers; the price was ¥87.98 in January and February 1944, and ¥91.93 in April. Advertisements boasted the following points:
- patented independent design;
- precise construction;
- excellent parallelism of the focusing plane;
- no need to remove the camera's back ("the same as on the imported product", i.e. the Rolleikin);
- slight telephoto effect given by the 75mm focal length;
- ability to take colour film or positive film.
- Advertisement on p.11 of Nihon Shashin Kōgyō Tsūshin, February 15, 1944, reproduced on p.75 of Hyaku-gō goto jūkai no kiroku.
- Advertisements for the Banzaikin in Shashin Kagaku January and April 1944, and advertisement on p.11 of Nihon Shashin Kōgyō Tsūshin, February 15, 1944, reproduced on p.75 of Hyaku-gō goto jūkai no kiroku.
- Advertisement for the Banzaikin in Shashin Kagaku July 1944, and advertisement on p.11 of Nihon Shashin Kōgyō Tsūshin, February 15, 1944, reproduced on p.75 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 by Banno Bōeki on p.75, corresponding to p.11 of the February 15, 1944 issue.