Minase
Minase Masterpiece 40 mm Mother-of-pearl 18k
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.
Minase · Masterpiece
Minase Masterpiece 40 mm Mother-of-pearl 18k
Reference 31790OR.66
Reference at a glance
- Brand
- Minase
- Collection
- Masterpiece
- Model
- Minase Masterpiece 40 mm Mother-of-pearl 18k
- Reference number
- 31790OR.66
- Year / era
- 2005 · 2000s — modern production
- Complication
- Perpetual calendar
- Movement
- Spring Drive
- Case material
- 18k rose gold
- Dial type
- Mother-of-pearl
- Strap / bracelet
- Alligator leather with folding clasp
- Water resistance
- 200 m
- Limited-edition status
- Regular production, not a limited edition
Case, dial & bracelet
- Case dimensions
- 40 mm
- Case thickness
- 8.8 mm
- Case material
- 18k rose gold
- Bezel
- Octagonal with 8 hexagonal screws
- Crystal
- Box sapphire with AR coating
- Dial
- Mother-of-pearl
- Hands
- Rhodium-plated baton hands with luminous fill
- Indexes
- Applied faceted white-gold indexes
- Bracelet / strap
- Alligator leather with folding clasp
- Clasp / buckle
- Folding clasp in matching case metal
- Water resistance
- 200 m
Movement
- Movement / calibre
- Calibre 72C — Spring Drive
- Movement type
- Automatic with micro-rotor
- Frequency
- 25,200 vph (3.5 Hz)
- Power reserve
- 65 hours
- Number of jewels
- 37 jewels
- Complications
- Perpetual calendar
- Functions
- Perpetual calendar, leap year
- Watchmaker
- Finishing, assembly and timing are carried out in the manufacture's own atelier.
Production & market
- Production period
- 2005 – 2016
- Limited-edition quantity
- Not applicable
- Current market information
- Values have stabilised after the 2022 correction; condition and box-and-papers drive the premium.
Designer
Jörg Hysek
Jörg Hysek left Rolex and Seiko's European studios to build a design practice in Geneva, giving houses such as Vacheron Constantin, Breguet, Seiko and TAG Heuer their sculptural, architecture-led cases before founding his own brand, HD3.
Historical significance
Minase Masterpiece 40 mm Mother-of-pearl 18k sits within Minase's Masterpiece line, introduced in 2005. It carries the house codes established since 2005 — 18k rose gold case, mother-of-pearl dial and spring drive — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- The bracelet tapers across its length, which is why the profile looks thinner on the wrist than the specification suggests.
- The movement's bridges are decorated even where they will never be seen once the watch is cased.
The House
Minase
Brand facts
- Founding year
- 2005
- Founder
- Kyowa Co. / Susumu Kitamura
- Headquarters
- Japan
- Tier
- Japanese
- Major collections
- Divido, Five Windows, Horizon, Masterpiece
- Signature technologies
- In-house hairspring production · Proprietary case-hardening and polishing
- Famous movements
- Automatic, 24 jewels · Eco-Drive solar quartz · High-accuracy quartz · Spring Drive
- Notable watches
- Minase Divido (2000) · Minase Horizon (2001) · Minase Uruga (2002)
Brand history
Minase has spent more than 21 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's Divido, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.
Kyowa Co. / Susumu Kitamura established Minase in 2005, working from Japan at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Minase calibre produced today.
Historical milestones
2005
Kyowa Co. / Susumu Kitamura founds Minase in Japan.
2024
Minase continues to produce Divido, Five Windows, Horizon and other icons in limited numbers.