I want to sort this Onsa automatic watch into my collection. It has an ETA movement which puzzles me a bit.
First of all, it has this cursed ETA-disease of putting the caliber markings directly (I mean absolutely perpendicular) under the balance wheel, whatever the reason is for this idiotic positioning (see an authorized dealer to find out?). Yes, there are other manufacturers who have these markings in strange places, but ETA has made an art of this.
For that reason, I can’t take any good pictures, but looking underneath with a loupe, it is clearly ETA 2453. The movement is marked ’30 jewels’, but I can find this specific movement only with 17/21/25 jewels in the Ranfft database and elsewhere. The ETA 2452 has a 30 jewels version, so I guess there is also a 2543 with 30 jewels.
If there is an even (not uneven) number of jewels, how is that added up? I am not totally familiar with the positioning of all the jewels in a watch movement. Is it something that you specifically see on automatic watches (leaving aside all the misleading jewel counts)?