|TKS shutter on a Frank Six|
image by Robert Smith (Image rights)
The TKS is Japanese leaf shutter, certainly made by Tōsei Kōki, mounted on the cameras made by that manufacturer. It has B, 1–200 speeds, flash synchronization and a self-timer. The name presumably stands for Tōsei Kōki Shutter.
List of cameras with a TKS shutter
The following cameras are known with a TKS shutter (not all the examples are concerned):