Citizen
Citizen Eco-Drive 41 mm Slate Sapphire
Photography on request
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.
Citizen · Eco-Drive
Citizen Eco-Drive 41 mm Slate Sapphire
Reference 78331OR.50
Reference at a glance
- Brand
- Citizen
- Collection
- Eco-Drive
- Model
- Citizen Eco-Drive 41 mm Slate Sapphire
- Reference number
- 78331OR.50
- Year / era
- 1981 · 1980s — quartz-crisis era
- Complication
- Time and date
- Movement
- High-accuracy quartz
- Case material
- Sapphire crystal case
- Dial type
- Slate grey
- Strap / bracelet
- White rubber velcro strap
- Water resistance
- 150 m
- Limited-edition status
- Regular production, not a limited edition
Case, dial & bracelet
- Case dimensions
- 41 mm
- Case thickness
- 11.3 mm
- Case material
- Sapphire crystal case
- Bezel
- Emerald-set
- Crystal
- Sapphire with internal AR treatment
- Dial
- Slate grey
- Hands
- Skeletonised sword hands, white luminescent
- Indexes
- Applied Roman numerals
- Bracelet / strap
- White rubber velcro strap
- Clasp / buckle
- Pin buckle in matching case metal
- Water resistance
- 150 m
Movement
- Movement / calibre
- Calibre 36F — High-accuracy quartz
- Movement type
- Automatic, self-winding
- Frequency
- 36,000 vph (5 Hz)
- Power reserve
- 55 hours
- Number of jewels
- 45 jewels
- Complications
- Time and date
- Functions
- Dive time, running seconds
- Watchmaker
- Assembled and regulated by a single watchmaker, who signs off the piece before casing.
Production & market
- Production period
- 1981 – 1987
- 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
Citizen Eco-Drive 41 mm Slate Sapphire sits within Citizen's Eco-Drive line, introduced in 1981. It carries the house codes established since 1918 — sapphire crystal case case, slate grey dial and high-accuracy quartz — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- The case is finished by hand, alternating polished and satin-brushed surfaces in a single pass so the edges stay razor sharp.
- The bracelet tapers across its length, which is why the profile looks thinner on the wrist than the specification suggests.
The House
Citizen
Brand facts
- Founding year
- 1918
- Founder
- Kamekichi Yamazaki
- Headquarters
- Japan
- Tier
- Japanese
- Major collections
- Eco-Drive, Promaster, Series 8, The Citizen, Attesa
- Signature technologies
- Certified chronometer regulation · Shock-absorbing movement mounting · Composite and ceramic case materials
- Famous movements
- High-accuracy quartz · Spring Drive · Automatic, 24 jewels · Eco-Drive solar quartz
- Notable watches
- Citizen Eco-Drive 41 mm Slate Sapphire (1981) · Citizen Eco-Drive 42 mm Black Grade (1995) · Citizen Eco-Drive 38 mm Slate 18k (1991) · Citizen Eco-Drive 38 mm Mother-of-pearl 18k (1975)
Brand history
Citizen has spent more than 108 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's Eco-Drive, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.
Kamekichi Yamazaki established Citizen in 1918, working from Japan at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Citizen calibre produced today.
Historical milestones
1918
Kamekichi Yamazaki founds Citizen in Japan.
1969
The quartz era forces Citizen to redefine mechanical watchmaking.
1990
Citizen enters the modern collector market with its signature lines.
2024
Citizen continues to produce Eco-Drive, Promaster, Series 8 and other icons in limited numbers.