Around 1960, Tissot launched a tiny handwound movement series for ladies’ watches with a diameter of only 6 3⁄4 lignes (15.1mm). It was produced several years and got two subsequent versions. This was the Tissot 709 series and the Tissot 709-1 described here was the first modification of the base movement Tissot 709.Video on YouTube
It is a contemporary construction with a directly driven center minute wheel. The round shape of the plates made it possible to use a relatively large screw-less ring balance.
The Tissot 709-1 was a rather high quality movement, you can see for example of the movement-side KIF Duofix bearing of the escapement wheel. Because of it, the escapement wheel is not only protected agains axial impacts, but this bearing is mainly used as a container for oil.
The screw-less ring balance, which is beared in two Incabloc shock protection bearings beats with rather modern 19800 A/h and controls a conventional swiss pallet lever escapement.
On the dial side, you can easily spot the second Incabloc bearing of the balance, as well, as the yoke winding system with its setting lever spring.
The minute wheel (at 4:30) has got four holes, which allows oling of the underlying driving wheel without dismounting.
Regarding the differents to the Tissot 709 and a larger cutout on the base plate for the yoke.
|Number of jewels:||17|
Nickel anular balance|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||2 hole(s)|
|Size:||6 3/4''' (measured: 15,3mm)|
Flume: K2 -|