Grand Seiko · Evolution 9 Collection
Grand Seiko SLGH005: specifications and what to check
Thirty-six thousand beats an hour and eighty hours of reserve at the same time, which is the unusual part. A box crystal, a display back, and 178 grams of steel on a 40mm case.
Reference SLGH005 · specifications read from the manufacturer on 2026-09-22 · listed as current
Specifications
As published by Grand Seiko. A field the manufacturer does not state is left out rather than filled in.
- Case
- Stainless steel, 40.0 mm
- Diameter
- 40 mm
- Thickness
- 11.7 mm
- Lug width
- 22 mm
- Lug to lug
- 47 mm
- Water resistance
- 10 bar
- Crystal
- Box shaped sapphire crystal, anti-reflective coating on inner surface
- Dial
- Described as silvery white with an intricate pattern expressing the white birch forests near Grand Seiko Studio Shizukuishi
- Case back
- See-through and screw case back
- Crown
- Screw-down
- Bracelet
- 22 mm band width, 190 mm band perimeter
- Clasp
- Folding clasp with push button release
Movement
- Calibre
- 9SA5
- Type
- Self-winding with manual-winding
- Power reserve
- Approximately 80 hours
- Frequency
- 36,000 vibrations per hour
- Notes
- 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 to check before you buy
- 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.
- Confirm the crown screws down cleanly and that the display back is properly seated. Both are threaded, and this case pairs a screw-down crown with a screw case back that has a window in it.
- Compare the weight in hand to the stated 178 grams. That is heavy for a 40mm watch, and the density is part of how the reference presents itself to a buyer.
Fast and long at once
The specification that makes this reference interesting is a pairing that normally involves a trade-off.
High-beat movements run at 36,000 vibrations per hour. More beats means finer averaging of positional error, and historically it also meant a shorter reserve, because the barrel empties faster.
The 9SA5 is specified at approximately 80 hours anyway. Grand Seiko attributes that to twin barrels and a Dual Impulse Escapement of its own design. Whatever the engineering, the practical number is what a dealer needs: a watch put down on Friday evening should still be running on Monday morning, which very few high-beat watches can claim.
Two accuracy figures, and they are not interchangeable
Grand Seiko publishes both, and the difference trips people up constantly.
Mean daily rate: +5 to −3 seconds per day. This is measured on the bare movement, before it goes into the case, in six positions under controlled conditions over twelve days.
Normal usage accuracy: +8 to −1 seconds per day. This is the figure for a watch being worn.
If you time an example on the wrist and it runs +6, you have not found a fault. You have found a watch performing inside its published worn specification. Quote the right number, to yourself and in your listing, and you will avoid both underselling a good example and overpromising on an average one.
A box crystal is an exposed part
The glass is box shaped sapphire with anti-reflective coating on the inner face. It rises above the case in a squared profile rather than sitting flush.
That shape is the design's signature and its vulnerability. Because the glass stands proud, it meets door frames and desk edges first, and the exposed vertical face at the perimeter is where chips start. Sapphire is extremely hard and genuinely brittle; it does not scratch, it fractures.
Hold the watch so light rakes across the crystal's edge and look along the whole circumference. A chip at the turn-down is easy to miss straight on and is immediately obvious from a low angle — and it is a real cost, because a shaped crystal is not a flat disc you can source generically.
The inner anti-reflective coating deserves its own look for the same reason it does on any coated crystal: you cannot reach it, so haze there means replacement.
Weight, size and how to describe it
Published dimensions: 40.0 mm diameter, 11.7 mm thick, 47.0 mm lug to lug, 22 mm lug width, and 178 grams complete.
Two of those are worth putting in front of a buyer explicitly. Forty-seven millimetres lug to lug is compact for the diameter, so this wears smaller than its case measurement suggests — a genuine selling point for someone worried about size. And 178 grams is substantial, which some buyers want and others do not.
Both figures come from the manufacturer. There is no reason to make a buyer guess at either.
Price references like this, faster
What a reference is worth at intake, what to check before you buy it, and where it sells best. Free guides for dealers.
Sources
Not affiliated with Grand Seiko. Specifications are read from the manufacturer's own published documentation on the date shown and may change; the manufacturer's current documentation governs.