Seiko 560 - Parts List
Seiko 560 Series – Technical Guide
Introduction
The Seiko 560 series (also written as Cal. 56xx) includes some of the most revered manual and automatic movements ever produced by Seiko. Most notably, the 5625, 5645, and 5646 movements were used in Grand Seiko watches and are renowned for their fine regulation, finishing, and chronometer-level accuracy.
These calibers were manufactured at Suwa Seikosha and are direct descendants of the Seiko 5200 series.
Core Movement Overview (Base Caliber: 560)
| Feature | Specification |
|---|---|
| Base Caliber | Seiko 560 (foundation for 5625, 5645, etc.) |
| Movement Type | Mechanical (manual or automatic, depending on variant) |
| Jewels | 25 or 28 (depending on model) |
| Beat Rate | 28,800 bph (8 beats/sec) |
| Hacking Seconds | Yes (on most Grand Seiko versions) |
| Manual Winding | Yes |
| Automatic Winding | Yes (on automatic versions) |
| Power Reserve | ~45 hours |
| Calendar | None / Date / Day-Date / Hi-Beat (depending on model) |
| Accuracy | Rated –3 to +6 sec/day (GS versions) |
| Shock Protection | Diashock |
Key Variants in the 560 Family
| Caliber | Function | Used In |
|---|---|---|
| 560 | Base movement (manual wind) | Rare prototypes |
| 5625A/B | Auto + date | Grand Seiko 56GS |
| 5626A/B | Auto + day-date | Grand Seiko 56GS |
| 5645A/B | Auto + date, Hi-Beat | Grand Seiko (Chronometer) |
| 5646A/B | Auto + day-date, Hi-Beat | Grand Seiko (Chronometer) |
| 5621 | Manual wind, no date | King Seiko or Seikomatic-R |
The most popular and collectible variants are 5645 and 5646, used in Grand Seiko 5645-7000/7005/7010 and 5646-7010 respectively.
Features & Engineering
1. Hi-Beat Performance
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28,800 bph (8 ticks per second), rare for the time
-
Ensures smoother hand motion and better accuracy potential
2. Fine Regulation System
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Some versions include a micro-adjustment screw
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High-quality balance assembly and hairspring
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Many models regulated to chronometer-grade specs
3. Calendar Mechanisms
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Instantaneous or semi-instantaneous date/day change
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Quickset date (and day for 5646) via crown in first position
Maintenance and Servicing
The 560 series movements are high-grade but serviceable. They are still supported by a number of watchmakers worldwide due to parts availability and modular design.
Service Interval:
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Every 5–7 years, depending on usage and storage conditions
Lubrication Points:
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Escape wheel pivots and pallet fork stones
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Center and third wheel arbors
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Rotor bearing (automatic models)
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Date jumper and calendar gear train
Common Issues & Fixes
| Symptom | Cause | Solution |
|---|---|---|
| Loses/gains time | Needs regulation or cleaning | Service and adjust regulator screw |
| Date doesn’t change properly | Jumper spring fatigue | Replace jumper or lubricate switch |
| Rotor noise (auto versions) | Rotor bearing wear | Clean or replace rotor bushing/bearing |
| Hands misaligned | Improper reset or collision | Realign hands carefully using hand press |
Notable Models
The Seiko 560 series movements powered some of the most famous Grand Seiko models, including:
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Grand Seiko 5646-7010 – Hi-Beat Day-Date
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Grand Seiko 5645-7000 – Hi-Beat Date
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Grand Seiko 5625-7000 – Standard Date
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Grand Seiko 5626-7110 – Day-Date variant
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King Seiko 5621-5000 – Manual wind, no calendar
Many of these watches featured hand-finished dials, Zaratsu polishing, and casebacks with lion or GS medallions.
Summary Table
| Attribute | Specification |
|---|---|
| Movement Series | Seiko 560 series (56GS, King Seiko) |
| Jewels | 25–28 |
| Beat Rate | 28,800 bph (Hi-Beat) |
| Winding | Automatic + Manual (varies) |
| Hacking Seconds | Yes (GS models) |
| Calendar | None / Date / Day-Date (varies) |
| Power Reserve | ~45 hours |
| Used In | Grand Seiko, King Seiko, Seikomatic |
Conclusion
The Seiko 560 movement family, especially the 5645 and 5646, represents the pinnacle of vintage Japanese watchmaking. With Hi-Beat frequency, excellent finishing, and a heritage linked to Grand Seiko’s pursuit of precision, these movements are coveted by collectors and still viable for everyday use if properly maintained.
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