According to Grand Seiko:
The caliber number is a four-digit number that indicates the model of a movement (mechanical part of a watch). The Grand Seiko watch is mounted with an exclusive caliber. The mechanical caliber number starts with “9S”, the spring drive caliber number starts with “9R” and the quartz caliber number starts with “9F”.※Some quartz caliber number starts with “8J” or “4J”.
The four-digit model number on the case back is the caliber number.In the case of mechanical models, the attached “Grand Seiko Standard Inspection Certificate” is printed with “Caliber No.” So, the caliber number can also be checked on the certificate.
Source: Grand Seiko 9S caliber manual
Trending Comments
Longines Caliber L836.6
The differenece is the beat rate. 3Hz vs 5Hz. 6 beats/s vs 10 beats/s.
Orient Caliber F6922
I've had my Mako and Ray Orient watches with these calibers, I guess. Their performance…
Invicta Caliber JSD-006ZY
Apart from the fact, that there is no further information about this caliber anywhere, it…
Seiko Instruments (SII) Caliber VH31
the VH-31 movement coupled with solar or kinetic in a Seiko watch would sell like…
Miyota/Citizen Caliber 9051
I have the 9051 in my Fujitsubo, it appears to be within 3 seconds. I'll…
Active Caliber Listings
I have the 9051 in my Fujitsubo, it appears to be within 3 seconds. I'll…
It might be a Chinese Standart-movement aka Tong Ji aka 7120 / SS7 with an…
Thank you for sharing your experience with the community. If possible, please submit images of…
Apart from the fact, that there is no further information about this caliber anywhere, it…
This £80 lorus has the y676c with Japan on the rotor