Grand Seiko · Heritage Collection and Evolution 9 Collection
Grand Seiko SBGA413 vs Grand Seiko SLGA021
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 | High-Intensity Titanium, 40.0 mm, described as a reborn 62GS design | Stainless steel, 40.0 mm, described as embodying the Evolution 9 Style |
| Thickness | 12.8 mm | 11.8 mm |
| Lug to lug | 47 mm | 47.9 mm |
| Lug width | 21 mm | 22 mm |
| Crystal | Box shaped sapphire crystal, anti-reflective coating on inner surface | Dual-curved sapphire crystal, anti-reflective coating on inner surface |
| Dial | Described as inspired by Hana-Ikada, spring cherry blossoms floating on a river | Blue with a textured pattern, described as expressing the surface of Lake Suwa before dawn |
| Case back | See-through and screw case back | Movement visible from the back, with a decoration described as Shinshu Frost |
| Bracelet | 21 mm band width, 202 mm band perimeter | 22 mm band width |
| Calibre | 9R65 | 9RA2 |
| Power reserve | Approximately 72 hours (3 days) | Approximately 120 hours (5 days) |
| Movement notes | Stated accuracy ±15 seconds per month (±1 second per day). Power reserve indicator. Listed as allergy-safe metal. Total weight 102 g. | 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. |
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
- Water resistance
- 10 bar
- Clasp
- Folding clasp with push button release
- Movement
- Spring Drive, self-winding with manual-winding
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 | Screw-down | not stated |
|---|---|---|
| Jewels | 30 | not stated |
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.
One survives the weekend and one does not
120 hours on the SLGA021 against 72 on the SBGA413. 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 case materials, different handling
The SBGA413 is titanium and the SLGA021 is steel. Different case materials mark, polish and refinish differently, so the condition language that fits one will mislead on the other. Photograph and describe each on its own terms.
Different movements to verify and to service
The SBGA413 runs the 9R65 and the SLGA021 the 9RA2. 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
SBGA413
- Check the reference number against the case dimensions before you list it. Two titanium Spring Drive watches in this collection share the 9R65 and differ by a millimetre of diameter, so the movement tells you nothing about which one you have.
- Inspect the box crystal's raised edge under raking light for flakes. A squared sapphire profile on a titanium case gives the glass no protection from a knock the case would otherwise take.
- Confirm the band perimeter suits the buyer. Grand Seiko states 202 mm here, which is generous, and a bracelet sized for a large wrist may need links the seller no longer has.
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.
Sources
- Grand Seiko official product page for reference SBGA413 (Heritage Collection; Automatic Spring Drive 3-Day; nickname Hana-Ikada) - Exterior: High-Intensity Titanium; 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 12.8mm; Band width: 21mm; Clasp: folding clasp with push button release; Band perimeter: 202mm; Caliber: 9R65; Movement type: Spring Drive self-winding with manual-winding; Power reserve: approx. 72 hours (3 days); Accuracy: +/-15 seconds per month (+/-1 second per day); Water resistance: 10 bar; Magnetic resistance: 4,800 A/m; Weight: 102 g; Other features: screw-down crown; allergy-safe metal; 30 jewels; power reserve indicator; described as the 62GS design reborn with a dial inspired by Hana-Ikada, spring cherry blossoms floating on a river — retrieved 2026-09-22
- 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
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.