The acronym TSK is found on at least two different Japanese leaf shutters.
At least one source also mentions a TSK logo on the Mykey-4 camera, see the corresponding page.
1930s or 1940s shutter
The first TSK shutter (5–250, B, T) appears on at least one Baby Germa made by Tōkyō Shashin Kōgaku Kōgyōsha, dating from the late 1930s or early 1940s. In this case, TSK certainly stands for Tōkyō Shashin Kōgaku.
The other TSK shutter is better known, and appears on various Japanese TLR cameras of the 1950s. All the examples observed have B, 1–200 speeds, and the name TSK is always inscribed on the speed rim.
Two versions are known, with or without a self-timer. The shutters mounted on the Alfaflex and some Cosmoflex II have no self-timer and have a black shutter plate inscribed TOYO S.K.CO. The version with a self-timer has a silver shutter plate, sometimes with a red TSK logo. It is found on the Princeflex and Elbowflex, which were made by Tōyō Seiki Kōgaku, and on some other TLR cameras.
It seems likely that TSK stands for Tōyō Seiki Kōgaku and that the shutters were made by that company; however, nothing is yet clearly known.
Cameras fitted with TSK shutters
Listing of a camera here should not be taken to mean that all examples of the camera were fitted with TSK shutters.
- Alfaflex (without a self-timer)
- Cosmoflex (with or without a self-timer)
- Elbowflex (self-timer)
- Orion Six (self-timer)
- Princeflex (self-timer)
- Example pictured in Sugiyama, item 4036.
- Sugiyama, Kōichi (杉山浩一); Naoi, Hiroaki (直井浩明); Bullock, John R. The Collector's Guide to Japanese Cameras. 国産カメラ図鑑 (Kokusan kamera zukan). Tokyo: Asahi Sonorama, 1985. ISBN 4-257-03187-5.