Tap the image to enlarge
Grand Seiko Heritage Collection Mount Iwate Autumn Dusk European Limited Edition 36.5mm Stainless Steel
Ref. SBGW303G
The dial takes its cue from the ridgelines of Mount Iwate as seen from the Shizukuishi studio where Grand Seiko makes its movements — a textured dark grey-green that shifts as the light moves across it, evoking the mountain's contours at the moment autumn dusk catches the peak. Against that surface, a gold-applied GS logo stands as the single bright accent, placed where the autumn moon would sit in the view that inspired the whole design. The edition was drawn for the European market and limited to 400 pieces, which makes it a considered thing rather than a catalogue entry. The 9S64 inside is a manufacture calibre built to a tolerance of +5 to −3 seconds per day, which is meaningfully tighter than the COSC standard. At 36.5mm across and 42.7mm lug to lug, it sits within the wrist rather than across it, and at 11.6mm the profile is slim enough that the case disappears under a shirt cuff entirely. The Zaratsu-polished flanks — the method Taro Tanaka formalised in 1967 as Grand Seiko's Grammar of Design — produce edges that read as lines rather than surfaces, catching the light in a way that photographs cannot quite capture and that takes a few days of wearing to stop noticing.
- Reference
- SBGW303G
- Brand
- Grand Seiko
- Collection
- Heritage
- Case size
- 36.5mm
- Case thickness
- 11.6mm
- Lug width
- 18mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Green
- Crystal
- Sapphire
- Movement
- Manual
- Calibre
- 9S64
- Water resistance
- 100m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Three-fold clasp
- Lume
- Luminous
- Condition
- Pre-owned
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 42.7mm
- Power reserve
- 72 hours
Learn more about Grand Seiko
Grand Seiko began in 1960 as Seiko's attempt to build a watch to the highest standard in the world, judged against Swiss chronometer criteria rather than Japanese ones. The first model met the Bureaux Officiels standard, and the ambition was explicit: not a good Japanese watch, but a better watch than the Swiss were making.
The 1967 Grammar of Design, laid down by Taro Tanaka, still governs the aesthetic. Flat surfaces and sharp facets rather than curves; hands and markers cut to catch light in defined planes; every surface either mirror-polished or perfectly flat, with no in-between. The polishing is done by hand on tin plates — Zaratsu — which produces distortion-free reflections and cannot be replicated by machine.
The precision case was made at observatory trials in the 1960s, where Grand Seiko movements placed among the leaders in Geneva and Neuchâtel before the competitions ended.
The house's distinctive technology is Spring Drive, introduced in 1999 after nearly three decades of development. A conventional mainspring drives the watch, but the escapement is replaced by an electromagnetic brake regulated by a quartz oscillator: mechanical power, quartz accuracy, and a seconds hand that sweeps without ticking at all.
Grand Seiko was separated into a standalone brand internationally in 2017, with dials frequently drawn from Japanese landscape — the Snowflake among the best known.
- 1960
- The first Grand Seiko is built to Swiss chronometer standards.
- 1967
- Taro Tanaka codifies the Grammar of Design.
- 1968
- The 61GS Hi-Beat reaches 36,000 vibrations per hour.
- 1999
- Spring Drive combines mechanical power with quartz regulation.
- 2017
- Established as an independent brand worldwide.
Also in 7 collections
This watch appears in the Grand Seiko Heritage range (7), Back in Stock (5,241), Stainless Steel Watches (3,391), Watches Under 37mm (1,830), Green Dial Watches (466), Pre-Owned, Ex-Display & Vintage Watches (356) and Limited Edition Watches (202).
Temporarily out of stock
Mappin & Webb is not currently taking orders for this reference. Last listed as available on 16 October 2026. Stock is checked nightly and this page updates when it returns.
What the specifications mean
Strengths
- 100m water resistance covers swimming and watersports
- 36.5mm suits most wrists
- 42.7mm lug-to-lug keeps the 36.5mm case wearable
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 100m it is rated for swimming and snorkelling, though not for diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is hand-wound, so it needs winding every day or two but never a battery.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 72 hours fully wound — enough to sit off the wrist over a weekend and still be running.
What size strap does it take?
18mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Will it fit my wrist?
Lug-to-lug is 42.7mm, which suits wrists from roughly 15cm (6 inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as men's, though at 36.5mm it sits in the range that suits anyone.
More Grand Seiko watches like the Heritage Collection Mount Iwate
In stock, and close on style and price
