The chinese ZSE Z-A was the first incarnation of the "First National Standard Movement", the first standardized mens' watch movement. It was made between 1972 and 1974, before it was superseded by the million-seller ZSH series.
The construction is very traditional and easy serviceable - the large four-leg ring balance contains a thick and rugged (hard to break accidentially) hairspring, which is connected to a moveable hairspring stud and whose effective length can be regulated directly on the hairspring key. The balance beats with 21600 A/h and is shock proctected. The shock protection system is made in China and its springs were available in many different shapes, starting from an Incabloc-like type to a "four leaf clover".
On the dial side, you see, whan was above described as "four leaf clover": The shock protection spring. It reminds a bit of a KIF flector. Otherwise, there are no surprises on the dial, and of course, this movement uses a yoke winding system.
This movement was kindly donated by Klaus Brunnemer. Thank you very much!