Grand Seiko
Evolution 9 Spring Drive 5 Days "Lake Suwa" SLGA021
Ref. SLGA021
2022–present · 40mm · caliber Grand Seiko Cal. 9RA2: Spring Drive, 120h (5-day) PR, 38j, 34mm x 5mm; measures its own temperature 540 times an hour to compensate the oscillator, rated to +/-0.5 sec a day and +/-10 sec a month; power reserve moved to the movement side to slim the case
- GPHG 2023EnteredHomme category
Entry to the Grand Prix d'Horlogerie de Genève is voluntary and made by the brand. An entry is a watch registered for that year's competition, not a jury verdict, and several large houses including Rolex, Patek Philippe and Omega do not take part at all.
What it was up against
Homme, GPHG 2023
The Homme category at GPHG 2023 held 27 entries. These are the other 26.
- Ferdinand Berthoud Chronomètre FB 3SPCWinner
- Simon Brette Chronomètre ArtisansWinner
- Arnold & Son DSTB 42 Platinum
- Audemars Piguet Code 11.59 by Audemars Piguet Starwheel
- B.R.M FF39x40 Bronze
- Bovet 1822 19Thirty Meteorite
- Charles Zuber Perfos 39 Steel
- Chopard Alpine Eagle 41 XPS
- Czapek Antarctique Révélation
- De Bethune DB28xs Starry Seas
- Gucci Timepieces Gucci 25H
- Hermès Hermès H08
- Laurent Ferrier Classic Micro-Rotor Evergreen
- Louis Vuitton Voyager Squelette
- Lucky Harvey Le Dragon
- LYH LYH-8 Astéroïde
- Mauron Musy Skeleton Armure
- Norqain Wild One Skeleton Turquoise
- Parmigiani Fleurier Tonda PF Micro-Rotor
- Raketa Ekranoplan
- Reservoir Kanister Silver Guilloché
- Ressence Type 1 Round
- Schwarz Etienne Geometry
- Trilobe Une Folle Journée Dune
- Xhevdet Rexhepi Minute Inerte
- Yosuke Sekiguchi Primevère
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Movement tier: unclassified
Medium-large: suits wrists 6.5 in+ (16.5 cm+)
40 mm case. Wears confidently on average to larger wrists. May overhang on slender builds.
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Authentication
Spring Drive is the easiest movement in watchmaking to verify by eye. The seconds hand glides with no steps at all, and nothing with a conventional escapement can imitate that convincingly.
Known issues in the market
- Replicas of Grand Seiko exist but almost always use a standard mechanical or quartz movement. Both step. Spring Drive does not, and a few seconds of watching the hand settles it.
- Grand Seiko runs several Spring Drive calibres. The 9RA2 in this reference keeps 120 hours and moves the power-reserve indicator to the movement side; the older 9R65 shows its reserve on the dial. A dial-side power reserve means a different watch.
- Evolution 9 and Heritage cases look similar in photographs and are not the same. Evolution 9 has the wider, flatter bezel and the shorter lugs.
| Area | What to check | What is correct | Red flag |
|---|---|---|---|
| hands | Seconds hand motion | A continuous glide with no perceptible steps anywhere in the sweep | Any stepping, however fine. An 8-beat mechanical still moves in discrete jumps under close watch |
| dial | Dial texture and text | The Lake Suwa pattern is stamped into the dial and catches light differently as the watch tilts. The dial reads "SPRING DRIVE" and "5 DAYS" | A printed or flat pattern, or a dial-side power-reserve arc, which belongs to the 9R65 generation |
| case | Zaratsu polishing | Flat mirror surfaces that reflect without distortion, meeting brushed surfaces along a crisp line | Rippled or wavy reflections in the polished flanks, which is what ordinary buffing looks like |
| movement | Calibre through the display back | 9RA2, 38 jewels, with the power-reserve indication on the movement side | A visible balance wheel oscillating back and forth. Spring Drive uses a glide wheel that spins continuously |
| case | Case dimensions | 40mm across, 11.8mm high, 100m water resistant with a screw-down crown | Dimensions materially away from those, which points at a different Evolution 9 reference |
Common legitimate replacements
- Spring Drive service is Grand Seiko or an authorised centre only; the glide wheel and IC are not third-party serviceable parts.
- Bracelet links and the clasp are routine replacements and should carry Grand Seiko markings.
Expert resources: Grand Seiko publishes the full specification for the SLGA021 on its own site, including the 9RA2 accuracy figures. Monochrome Watches and Fratello both covered the reference at launch.
