The 9581 motion, which powers the reissued 1988 Grand Seiko SBGS001/002, featured each a 6-marked regulating bolt and what gave the impression to be 5 digital contact surfaces.
I might additionally like to say the query I requested some time in the past to which @Bauta replied that the 9581 was a “9F81”.
https://www.watchuseek.com/threads/seiko-9f81.5524037/post-57162209
Though I settle for his reply, we will speculate that 9F could also be a mechanical redesign and enchancment that carried the digital aspect of the 95xx caliber into the brand new millennium, beginning with the 1993 SBGT001
The Caliber 95xx household is a post-twin quartz Haq that originated within the early Nineteen Eighties as Caliber 9520, a 2nd stage twentieth era spy motion for the stylish rectangular gold case watches of the time, which ultimately acquired the identify Dolce. (Later fashions with caliber 9531.)
The related level for this thread is that the 952x/9531 used an analogue regulation screw, which was then changed with what seems to be like a 9F type regulation screw and digital connectors on the 9581 simply 5 years later. Together with a re-evaluation to espionage degree 10.
A side-by-side comparability of the 95xx analog and digital PCBs may be useful in understanding the 9F.
