Grand Seiko · Evolution 9 Collection and Evolution 9 Collection
Grand Seiko SLGA021 vs Grand Seiko SLGH005
11 published specifications differ between these two, and 4 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.
What differs
| Specification | ||
|---|---|---|
| Case | Stainless steel, 40.0 mm, described as embodying the Evolution 9 Style | Stainless steel, 40.0 mm |
| Thickness | 11.8 mm | 11.7 mm |
| Lug to lug | 47.9 mm | 47 mm |
| Crystal | Dual-curved sapphire crystal, anti-reflective coating on inner surface | Box shaped sapphire crystal, anti-reflective coating on inner surface |
| Dial | Blue with a textured pattern, described as expressing the surface of Lake Suwa before dawn | Described as silvery white with an intricate pattern expressing the white birch forests near Grand Seiko Studio Shizukuishi |
| Case back | Movement visible from the back, with a decoration described as Shinshu Frost | See-through and screw case back |
| Bracelet | 22 mm band width | 22 mm band width, 190 mm band perimeter |
| Calibre | 9RA2 | 9SA5 |
| Movement | Spring Drive, self-winding with manual-winding | Self-winding with manual-winding |
| Power reserve | Approximately 120 hours (5 days) | Approximately 80 hours |
| Movement notes | Stated accuracy ±10 seconds per month (±0.5 second per day). Described as compensating for variations in the oscillator's performance by measuring the temperature 540 times per hour. The power reserve indicator is on the back rather than the dial, which Grand Seiko says slims the profile. Total weight 176 g. | Mean daily rate +5 to −3 seconds per day; normal usage accuracy +8 to −1 seconds per day. Described as a Grand Seiko-exclusive automatic movement with a Dual Impulse Escapement and twin barrels. Total weight 178 g. |
What is identical
Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.
- Diameter
- 40 mm
- Lug width
- 22 mm
- Water resistance
- 10 bar
- Clasp
- Folding clasp with push button release
Stated for one, not the other
These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.
| Crown | not stated | Screw-down |
|---|---|---|
| Frequency | not stated | 36,000 vibrations per hour |
What the differences cost you
Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.
Two different ownership conversations
The SLGA021 is Spring Drive and the SLGH005 is self-winding. That changes what a buyer needs telling at handover, and it changes intake: a hand-wound watch has no rotor to mask a tired mainspring, and a stopped quartz watch is usually a battery rather than a fault.
One survives the weekend and one does not
120 hours on the SLGA021 against 80 on the SLGH005. Below about sixty hours a watch left off the wrist from Friday is stopped by Monday. Wind both fully at intake and confirm they reach the stated figure — a short reserve leaves a tired barrel nowhere to hide, and it is the kind of fault a buyer reports in week two.
Different movements to verify and to service
The SLGA021 runs the 9RA2 and the SLGH005 the 9SA5. Two consequences at intake: the service history that is normal for one calibre is not evidence about the other, and the calibre is the check that catches a movement swapped into the wrong case. Confirm the movement matches the reference rather than assuming it from the dial.
What to check on each
SLGA021
- Turn the watch over to read the power reserve. On this calibre the indicator is on the back, so an inspection that never leaves the dial side has skipped the most useful gauge the watch has.
- Allow five days, not one, to test the reserve properly. A movement specified at approximately 120 hours can hide a weak barrel through an overnight check that a shorter-reserve watch would fail immediately.
- Time it against ±10 seconds per month rather than a daily figure. That works out near half a second a day, so a watch losing several seconds daily is far outside its own specification.
SLGH005
- Time it over a full day against the two published figures. Grand Seiko gives a mean daily rate and a separate normal usage accuracy, so judge a worn watch against the wider of the two rather than the laboratory number.
- Study the box crystal from a low angle for chips at the edge where the glass turns down. A box profile stands proud of the case, takes knocks the bezel would otherwise absorb, and is an expensive part to replace.
- Ask when it was last serviced and treat a vague answer seriously. A movement beating 36,000 times an hour puts more cycles through its parts in a year than a slower one does, whatever its reserve.
Sources
- Grand Seiko official product page for reference SLGA021 (Evolution 9 Collection; Spring Drive 5 Days) - Exterior: stainless steel; Glass: dual-curved sapphire crystal with anti-reflective coating on inner surface; Case size: diameter 40.0mm; lug-to-lug 47.9mm; thickness 11.8mm; Band width: 22mm; Clasp: folding clasp with push button release; Caliber: 9RA2; Movement type: Spring Drive self-winding with manual-winding; Power reserve: approx. 120 hours (5 days); Accuracy: +/-10 seconds per month (+/-0.5 second per day); Water resistance: 10 bar; Magnetic resistance: 4,800 A/m; Weight: 176 g; Other features: power reserve indicator; caliber 9RA2 described as compensating for variations in the oscillator's performance by measuring the temperature 540 times per hour, with the power reserve indicator placed on the back to slim the profile, and a case back decoration described as Shinshu Frost; blue dial described as expressing the surface of Lake Suwa before dawn — retrieved 2026-09-22
- Grand Seiko official product page for reference SLGH005 (Evolution 9 Collection; Hi-Beat 36000 80 Hours; nickname White Birch) - Exterior: stainless steel; Case back: see-through and screw case back; Glass: box shaped sapphire crystal with anti-reflective coating on inner surface; Case size: diameter 40.0mm; lug-to-lug 47.0mm; thickness 11.7mm; Band width: 22mm; Clasp: folding clasp with push button release; Band perimeter: 190mm; Caliber: 9SA5; Movement type: self-winding with manual-winding; Power reserve: approx. 80 hours; Mean daily rate: +5 to -3 seconds per day; Normal usage accuracy: +8 to -1 seconds per day; Water resistance: 10 bar; Magnetic resistance: 4,800 A/m; Weight: 178 g; Other features: screw-down crown; described as a Grand Seiko-exclusive automatic movement with Dual Impulse Escapement and twin barrels achieving 36,000 vibrations per hour; dial described as silvery white with an intricate pattern expressing white birch forests near Grand Seiko Studio Shizukuishi — retrieved 2026-09-22
Not affiliated with Grand Seiko. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.