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Grand Seiko Sport Collection 40mm Stainless Steel
Ref. SBGX343
The SBGX343 sits within Grand Seiko's lineage of anti-magnetic tool watches, descending from the SBGV243 and SBGV245 but arriving with a cleaner dial, no date, and water resistance pushed to 200 metres. The nickname "Tough Quartz" is earned rather than marketed: the 9F61 calibre holds to ±10 seconds per year, achieves that through a twin-pulse motor that drives heavier hands without the stuttering second common to lesser quartz movements, and is built to resist the magnetic fields that would compromise a mechanical. The case carries angular, muscular lugs and a flat bezel where the top face is hairline-brushed and the bevelled sides are Zaratsu-polished — two finishing textures that read as a deliberate contrast in most lighting. At 11.7mm thick and 45.3mm lug to lug, it wears closer to a sports watch than a dress one, but not aggressively so. The crown sitting at four o'clock rather than three means it never presses into the wrist during a full day on the bracelet. The matte black dial uses LumiBrite in two colours: cyan on the standard indices and hands, green reserved for the cardinal markers at twelve, three, six and nine. In complete darkness the four green points allow immediate orientation before the eye adjusts to read the others.
- Reference
- SBGX343
- Brand
- Grand Seiko
- Collection
- Sport Collection
- Case size
- 40mm
- Case thickness
- 11.7mm
- Lug width
- 20mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Black
- Crystal
- Sapphire
- Movement
- Quartz
- Calibre
- 9F61
- Functions
- Moonphase
- Water resistance
- 200m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Three-fold clasp
- Lume
- LumiBrite
- Condition
- Pre-owned
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 45.3mm
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 5 collections
This watch appears in Back in Stock (4,191), Stainless Steel Watches (2,819), Sports Watches (756), Dive Watches (535) and Pre-Owned, Ex-Display & Vintage Watches (355).
Temporarily out of stock
Mappin & Webb is not currently taking orders for this reference. Last listed as available on 13 October 2026. Stock is checked nightly and this page updates when it returns.
What the specifications mean
A watch built to be worn hard and got wet.
Strengths
- 200m water resistance, rated for actual diving
- 40mm suits most wrists
- 45.3mm lug-to-lug keeps the 40mm case wearable
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Grand Seiko Sport Collection alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SBGX343 | W6700255 |
|---|---|---|
| Price | £2,450 | £3,250 |
| Case size | 40mm | 36mm |
| Water resistance | 200m | 30m |
| Movement | Quartz | Quartz |
| Strap | Stainless steel bracelet | Leather strap |
| This watch |
|
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 200m it is rated for swimming, snorkelling and recreational 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?
Yes. It is quartz, so expect a battery change every two to three years at a jeweller.
Quartz, automatic and solar comparedWhat size strap does it take?
20mm. 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 45.3mm, which suits wrists from roughly 16cm (6¼ 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 40mm it sits in the range that suits anyone.
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