Front view
Dial, hands and bezel as delivered.
Case-back view
Case-back engraving and, where fitted, the sapphire display.
Movement
Calibre with its finishing and decoration.
On the wrist
Worn shot for proportion and strap drape.
Seiko · King Seiko
Seiko King Seiko 40 mm Blue Carbon
Reference 20420OR.31
Reference at a glance
- Brand
- Seiko
- Collection
- King Seiko
- Model
- Seiko King Seiko 40 mm Blue Carbon
- Reference number
- 20420OR.31
- Year / era
- 2003 · 2000s — modern production
- Complication
- Moon phase
- Movement
- Spring Drive
- Case material
- Carbon TPT
- Dial type
- Blue "Grande Tapisserie"
- Strap / bracelet
- Milanese mesh
- Water resistance
- 200 m
- Limited-edition status
- Regular production, not a limited edition
Case, dial & bracelet
- Case dimensions
- 40 mm
- Case thickness
- 8.1 mm
- Case material
- Carbon TPT
- Bezel
- Emerald-set
- Crystal
- Box sapphire with AR coating
- Dial
- Blue "Grande Tapisserie"
- Hands
- Skeletonised sword hands, white luminescent
- Indexes
- Applied Roman numerals
- Bracelet / strap
- Milanese mesh
- Clasp / buckle
- Titanium deployant clasp
- Water resistance
- 200 m
Movement
- Movement / calibre
- Calibre 30D — Spring Drive
- Movement type
- Manual-winding
- Frequency
- 36,000 vph (5 Hz)
- Power reserve
- 72 hours
- Number of jewels
- 45 jewels
- Complications
- Moon phase
- Functions
- Hours, minutes, seconds, date
- Watchmaker
- The calibre is built in-house and adjusted in five positions before delivery.
Production & market
- Production period
- 2003 – 2017
- Limited-edition quantity
- Not applicable
- Current market information
- Thin secondary-market supply — pricing is set piece by piece at auction.
Designer
Marc Newson
Marc Newson is an Australian industrial designer whose work spans Qantas cabins, Apple hardware and Jaeger-LeCoultre's Atmos clocks; his watch design reduces the object to pure geometry and legibility.
Historical significance
Seiko King Seiko 40 mm Blue Carbon sits within Seiko's King Seiko line, introduced in 2003. It carries the house codes established since 1881 — carbon tpt case, blue "grande tapisserie" dial and spring drive — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- The reference was originally planned as a one-year run and stayed in the catalogue for well over a decade.
- The bracelet tapers across its length, which is why the profile looks thinner on the wrist than the specification suggests.
The House
Seiko
Brand facts
- Founding year
- 1881
- Founder
- Kintaro Hattori
- Headquarters
- Japan
- Tier
- Japanese
- Major collections
- Prospex, Presage, King Seiko, Astron, 5 Sports
- Signature technologies
- In-house hairspring production · Proprietary case-hardening and polishing · Hand-applied guilloché dials
- Famous movements
- Eco-Drive solar quartz · High-accuracy quartz · Spring Drive · Automatic, 24 jewels
- Notable watches
- Seiko Prospex 36 mm Green Stainless (1952) · Seiko Prospex 38 mm Black 18k (1977) · Seiko Prospex 38 mm Meteorite Platinum (1972) · Seiko Prospex 42 mm Green Sapphire (1997)
Brand history
Seiko has spent more than 145 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's Prospex, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.
Kintaro Hattori established Seiko in 1881, working from Japan at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Seiko calibre produced today.
Historical milestones
1881
Kintaro Hattori founds Seiko in Japan.
1899
Seiko earns its first international recognition for precision timekeeping.
1969
The quartz era forces Seiko to redefine mechanical watchmaking.
1990
Seiko enters the modern collector market with its signature lines.
2024
Seiko continues to produce Prospex, Presage, King Seiko and other icons in limited numbers.