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Seiko

Movements used by Grand Seiko and Credor

 

Seiko makes an extensive assortment of movements. The highest quality and accuracy movements are in Grand Seiko and Credor watches, and fall into three groups:

MECHANICAL (manual or automatic)







GRAND SEIKO MECHANICAL MOVEMENTS


Movement

Mean daily rate

Accuracy

Power reserve

Vibrations

Jewels

Features

Manual-winding Mechanical Hi-Beat 36000 80 Hours

Caliber 9SA4

(Manual winding mechanical)

+5 to -3 sec/day

+8 to -1 sec/day

Approx. 80 hours

36,000/hr (10 beats/sec)

47 jewels

· Dual Impulse Escapement 

· Twin barrels 

· Power reserve indicator

Hi-Beat 36000 3-Day Chronograph

Caliber 9SC5

(Automatic or manual winding)

+5 to -3 sec/day

+8 to -1 sec/day

Approx. 72 hours

36,000/hr (10 beats/sec)

60 jewels

-Chronograph 

-Dual Impulse Escapement 

-Twin barrels

Hi-Beat 36000 80 Hours

Caliber 9SA5

(Automatic or manual winding )

+5 to -3 sec/day

+8 to -1 sec/day

Approx. 80 hours

36,000/hr (10 beats/sec)

47 jewels

-Dual Impulse Escapement 

-Twin barrels 

-Instant date change mechanism

Mechanical Hi-Beat 36000 GMT

Caliber 9S86

(Automatic or manual winding)

+5 to -3 sec/day

+8 to -1 sec/day

Approx. 55 hours

36,000/hr (10 beats/sec)

37 jewels

-Dual time function with 24-hr hand 

-Quick correction function of time difference adjusting to a calendar

Mechanical Hi-Beat 36000

Caliber 9S85

(Automatic or manual winding)

+5 to -3 sec/day

+8 to -1 sec/day

Approx. 55 hours

36,000/hr (10 beats/sec)

37 jewels

-Date display

Automatic 3-Day Power Reserve

Caliber 9S68

(Automatic or manual winding)

+5 to -3 sec/day

+10 to -1 sec/day

Approx. 72 hours

28,800/hr (8 beats/sec)

35 jewels

-Date display

Automatic 3-Day Power Reserve GMT

Caliber 9S66

(Automatic or manual winding)

+5 to -3 sec/day

+10 to -1 sec/day

Approx. 72 hours

28,800/hr (8 beats/sec)

35 jewels

-Dual time function with 24-hr hand 

-Quick correction function of time difference adjusting to a calendar

Automatic 3-Day Power Reserve

Caliber 9S65

(Automatic or manual winding)

+5 to -3 sec/day

+10 to -1 sec/day

Approx. 72 hours

28,800/hr (8 beats/sec)

35 jewels

-Date display

Manual-winding

Caliber 9S64

(Manual winding mechanical )

+5 to -3 sec/day

+10 to -1 sec/day

Approx. 72 hours

28,800/hr (8 beats/sec)

24 jewels

-

Manual-winding w/small seconds hand

Caliber 9S63

(Manual winding mechanical )

+5 to -3 sec/day

+10 to -1 sec/day

Approx. 72 hours

28,800/hr (8 beats/sec)

33 jewels

-Power reserve indicator 

-Small second hand

Small Size Automatic

Caliber 9S27

(Automatic or manual winding)

+8 to -3 sec/day

+10 to -5 sec/day

Approx. 50 hours

28,800/hr (8 beats/sec)

35 jewels

-Date display


As you can see from the illustrations, the different movements can fit into any type of case, whether the crown is on the left, right, top or bottom (sorry, I am writing this on April Fool's Day).

SPRING DRIVE (manual or automatic)





GRAND SEIKO SPRING DRIVE MOVEMENTS

Movement

Accuracy

Power reserve

Number of jewels

Other Features

Spring Drive U.F.A.

Caliber 9RB2

(Automatic with manual winding)

±20 seconds per year !

(±3 second per month)

Approx.72 hrs (3 days)

34 jewels

-Offset Magic Lever 

-One-piece Center Bridge 

-Power-reserve indicator 

-Date display

Spring Drive 5 Days

Caliber 9RA2

(Automatic with manual winding)

±10 seconds per month (±0.5 second per day)

Approx.120 hrs (5 days)

38 jewels

-Offset Magic Lever 

-Dual-size Barrels 

-One-piece Center Bridge 

-Power reserve indicator

Spring Drive 5 Days

Caliber 9RA5

(Automatic with manual winding)

±10 seconds per month (±0.5 second per day)

Approx.120 hrs (5 days)

38 jewels

-Offset Magic Lever 

-Dual-size Barrels 

-One-piece Center Bridge 

-Power reserve indicator

Manual-winding 8-Day Power Reserve Spring Drive

Caliber 9R01

(Manual winding)

±10 seconds per month (±0.5 second per day)

Approx.192 hrs

56 jewels

-Power reserve indicator 

-Quick adjustment

Manual-winding Spring Drive

Caliber 9R02

(Manual winding)

±15 seconds per month (±1 second per day)

Approx.84 hrs

39 jewels

-Torque Return System 

-Dual-Spring Barrel 

-Power reserve indicator

Automatic Spring Drive 3-Day Chronograph GMT

Caliber 9R96

(Automatic with manual winding)

±10 seconds per month (±0.5 second per day)

Approx.72 hrs

50 jewels

-Power reserve indicator 

-Dual time function with 24-hour hand 

-Quick time/date adjustment

-Stopwatch function

Automatic Spring Drive 3-Day Chronograph GMT

Caliber 9R86

(Automatic with manual winding)

±15 seconds per month (±1 second per day)

Approx.72 hrs

50 jewels

-Power reserve indicator 

-Dual time function with 24-hour hand 

-Quick time/date adjustment

-Stopwatch function

Automatic Spring Drive 3-Day GMT

Caliber 9R66

(Automatic with manual winding)

±15 seconds per month (±1 second per day)

Approx.72 hrs

30 jewels

-Power reserve indicator 

-Dual time function with 24-hour hand 

-Quick time/date adjustment

Automatic Spring Drive 3-Day

Caliber 9R65

(Automatic with manual winding)

±15 seconds per month (±1 second per day)

Approx.72 hrs

30 jewels

-Power reserve indicator 

-Date display

Automatic Spring Drive 3-Day GMT

Caliber 9R16

(Automatic with manual winding)

±10 seconds per month (±0.5 second per day)

Approx.72 hrs

30 jewels

-Power reserve indicator 

-Dual time function with 24-hour hand 

-Quick time/date adjustment

Manual-winding Spring Drive

Caliber 9R31

(Manual winding)

±15 seconds per month (±1 second per day)

Approx.72 hrs

30 jewels

-Dual-Spring Barrel 

-Power reserve indicator

Automatic Spring Drive 3-Day

Caliber 9R15

(Automatic with manual winding)

±10 seconds per month (±0.5 second per day)

Approx.72 hrs

30 jewels

-Power reserve indicator






QUARTZ (manual or just kidding, to see if you are paying attention)

GRAND SEIKO QUARTZ MOVEMENTS

Movement

Accuracy

Battery life

Features

Date Display with GMT Function

Caliber 9F86

±10 sec/yr

Approx. 3 years

-Instant date change mechanism 

-Dual time function with 24-hour hand 

-Quick time/date adjustment

Display

Caliber 9F85

±10 sec/yr

Approx. 3 years

-Instant date change mechanism 

-Quick time/date adjustment

Date Display

Caliber 9F62

±10 sec/yr

Approx. 3 years

-Instant date change mechanism

Slim three hand movement

Caliber 9F61

±10 sec/yr

Approx. 3 years

-

Slim three hand movement

Caliber 9F51

±10 sec/yr

Approx. 3 years

-


REAL LIFE IMAGES

I think this was the last GS quartz battery I changed:









Compare to a standard movement


Here are some Credor movements in situ: Automatic mechanical (spacer ring removed)



Manual Spring Drive



Mechanical Manual skeleton



Compare these movement finishes to typical Seiko model movement finishing:





I hope these figures are illuminating.


Cheers,

Cazalea

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Time for the annual recap of Credor & Grand Seiko models

 
By: cazalea : April 2nd, 2026-17:50
This is a challenging task, for despite these brands being a fraction of Seiko's production, they add up to a lot of watches! Let's start with Credor, because it's alphabetically first, and much easier to summarize. There are three lines: Goldfeather, Loc...  

Movements used by Grand Seiko and Credor

 
By: cazalea : April 2nd, 2026-18:03
Seiko makes an extensive assortment of movements. The highest quality and accuracy movements are in Grand Seiko and Credor watches, and fall into three groups: MECHANICAL (manual or automatic) GRAND SEIKO MECHANICAL MOVEMENTS Movement Mean daily rate Accu...  

Thank you for this Credor recap!

 
By: quattro : April 2nd, 2026-18:48
I still have to see an Eichi in person someday... Best, Emmanuel

Grand Seiko Models for 2026 (listed in ENGLISH / US MARKETS)

 
By: cazalea : April 2nd, 2026-20:10
Masterpiece Collection The Masterpiece Collection represents the pinnacle of Grand Seiko, drawing from two elite teams: Spring Drives come from the elite Micro Artist Studio in Nagano Prefecture, while mechanical watches are made within Atelier Ginza, in ...  

Kuon is in the Japanese only part of the site, not in English anywhere

 
By: cazalea : April 2nd, 2026-21:34
Probably didn't make a deal with US distributors to sell or support it, so "shhh, mum's the word". You have family picking it up, right? ...  

Thanks much for this!

 
By: S F : April 3rd, 2026-06:56
There are just way too many, think some consolidation will be good. Coincidentally, just collected a Credor….To be continued 😁

Credor with 6898 movement

 
By: Nicetomeetyou : April 4th, 2026-13:37
Thanks so much for posting on GS/Credor. Do you know if those movements are reliable or are they fragile? I know they are thin and typically in dress watches. Would be a pain if I had to send back to Japan for servicing or can they be serviced at GS servi...