WatchUSeek Watch Forums WatchUSeek Watch Forums Mandaue
Solely due to the generosity of @CitizenPromaster , I have come across a gold mine of technical information on Seiko's 9RA second-generation Spring Drive movement in the form of a 14-page Japanese-language technical paper published by the Japan Horological Society (日本時計学会) in their journal メカトロニクス (translates to 'Micromechatronics')
Out of respect for possible copyright, I will not (yet) post the entire paper…
