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 Edit
The following cameras are known with a TKS shutter (not all the examples are concerned):