With thanks to RB for the magnificent photos of this watch with complete accessories!
Probably this movement was originally in a solid gold case that is likely to be like a gold smelter victim...
The Junghans 683.75 is the version with Reed's regulator.
Additional information:
A watch of superlatives: Junghans J83
The discovery of a rarity: A special Junghans J83
Junghans J83; Junghans 683.71; Version with 28 Jwls
After 1964 Junghans ceased production of in-house Chronometers with automatic movements, helping itself with ETA movements.