Citizen
Citizen Series 8 36 mm Mother-of-pearl 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 · Series 8
Citizen Series 8 36 mm Mother-of-pearl Sapphire
Reference 91636OR.27
Reference at a glance
- Brand
- Citizen
- Collection
- Series 8
- Model
- Citizen Series 8 36 mm Mother-of-pearl Sapphire
- Reference number
- 91636OR.27
- Year / era
- 1955 · 1950s — pre-quartz mechanical era
- Complication
- Time only
- Movement
- High-accuracy quartz
- Case material
- Sapphire crystal case
- Dial type
- Mother-of-pearl
- Strap / bracelet
- Milanese mesh
- Water resistance
- 50 m
- Limited-edition status
- Regular production, not a limited edition
Case, dial & bracelet
- Case dimensions
- 36 mm
- Case thickness
- 8.8 mm
- Case material
- Sapphire crystal case
- Bezel
- Octagonal with 8 hexagonal screws
- Crystal
- Anti-reflective sapphire, double-domed
- Dial
- Mother-of-pearl
- Hands
- Mercedes hour hand with Chromalight display
- Indexes
- Printed minute track with applied batons
- Bracelet / strap
- Milanese mesh
- Clasp / buckle
- Triple-folding clasp with safety catch
- Water resistance
- 50 m
Movement
- Movement / calibre
- Calibre 42E — High-accuracy quartz
- Movement type
- Manual-winding
- Frequency
- 36,000 vph (5 Hz)
- Power reserve
- 72 hours
- Number of jewels
- 31 jewels
- Complications
- Time only
- Functions
- Dive time, running seconds
- Watchmaker
- The calibre is built in-house and adjusted in five positions before delivery.
Production & market
- Production period
- 1955 – 1960
- Limited-edition quantity
- Not applicable
- Current market information
- Consistently trades above retail; waiting lists at authorised dealers remain long.
Designer
In-house design studio
The reference was drawn by the manufacture's internal design office, where case, dial and movement architects work alongside the watchmakers rather than as an outside commission.
Historical significance
Citizen Series 8 36 mm Mother-of-pearl Sapphire sits within Citizen's Series 8 line, introduced in 1955. It carries the house codes established since 1918 — sapphire crystal case case, mother-of-pearl dial and high-accuracy quartz — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- The movement's bridges are decorated even where they will never be seen once the watch is cased.
- The case is finished by hand, alternating polished and satin-brushed surfaces in a single pass so the edges stay razor sharp.
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.