The Perpetual Calendar Dressed in Tantalum Armour

The H. Moser & Cie. perpetual calendar is widely considered to be the most legible and easy to set on the market, as it can be adjusted both forwards and backwards at any time of day. In 2023, H. Moser & Cie. has introduced this iconic model with a tantalum case – the first ever use of this rare and prestigious metal in the brand's history. In shades of anthracite and blue, this unique material is enhanced by the ancestral technique of enamelling, featuring vibrant colours and an ultra-contemporary hammered texture to bring the Endeavour Perpetual Calendar Tantalum Blue Enamel to life.
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Discovered in 1802 by Swede Anders Gustav Ekeberg, tantalum is a highly dense and extremely strong metal. Tantalum surfaces in contact with air develop a fine layer of oxidation that protects the metal against aggression. Tantalum offers anti-corrosive properties, and does not react with most chemical agents or dissolve in acid. This extremely malleable metal is both hard and ductile, which means it can be easily drawn out and worked with precision and finesse. With a melting point of around 3000 °C, it requires advanced metallurgical expertise to machine. Its very dark grey colour is enhanced by bluish reflections, and does not tarnish. An exceptionally stable metal, tantalum combines beauty with durability. And, as Edouard Meylan, CEO of H. Moser & Cie., explains, while it certainly offers some interesting special properties, it was also a personal choice: "When I was 18, my parents gave me my first Haute Horology watch, which was made from tantalum. Ever since then, I have dreamed of introducing this metal at H. Moser & Cie., in spite of the challenges it poses. It took more than two years of testing before we were able to polish the surfaces of our case, a feat that few have been able to match, with most preferring to sandblast or satin-finish tantalum".

Courtesy of H. Moser & Cie.

An iconic model, the perpetual calendar by H. Moser & Cie. is known for its complex movement, which nevertheless boasts unrivalled ease of use. The absence of a subdial and date disc makes it very easy to read. With the Endeavour Perpetual Calendar Tantalum Blue Enamel, H. Moser & Cie. takes its minimalist philosophy even further by removing the brand logo and all indices except for those at 12 and 6 o'clock, in order to showcase the full beauty of the "Grand Feu" enamel dial. Starting with a pattern engrained onto a gold base, as if hammered, four different colour pigments are washed, finely crushed, then applied to create an ombré effect. Careful work and limitless patience are required for the master enameller to painstakingly apply the pigments, adding them one by one so that the colours oxidise and meld together when heated in the furnace, without any pixellation. A translucent "Grand Feu" enamel dial must be fired twelve times in total to create the signature H. Moser & Cie. fumé effect. Each dial is unique. The finish is remarkable: resolutely contemporary, with a particularly complex texture and an intense hue christened Abyss Blue. At the centre, the small hand indicates the months, while a very large date window at 3 o'clock, with the "Flash Calendar" function providing an instant date change at midnight and a power reserve indicator at 9 o'clock displaying the movement's seven days of autonomy, complete the piece. The time and date are easy to set using the crown, and can be changed at any time of the day.

Courtesy of H. Moser & Cie.

H. Moser & Cie. has revolutionised the perpetual calendar by transforming a complication designed for the most discerning of collectors into a watch that even a child could operate. The resulting aesthetic is instantly recognisable, proving that real luxury is a question of identity – even without obvious markers.

H. Moser & Cie.'s own and unique take on Haute Horlogerie.

Courtesy of H. Moser & Cie.


Endeavour Perpetual Calendar Tantalum Blue Enamel, reference 1800-2000, tantalum and steel model, Abyss Blue fumé dial, grey kudu leather strap



Diameter: 42.0 mm

Height: 13.1 mm

Curved sapphire crystal

Steel case-back with curved sapphire crystal

Steel crown adorned with an "M"


Abyss Blue fumé "Grand Feu" enamel with hammered texture

Leaf-shaped hands

Small arrow-shaped centre hand indicating the months

Big date display


Hand-wound HMC 800 Manufacture calibre

Diameter: 34.0 mm or 15 lignes

Height: 6.3 mm

Frequency: 18,000 Vib/h

32 jewels

Power reserve: minimum 7 days

Hacking seconds

Double barrel

Interchangeable Moser escapement

Original Straumann® hairspring

Pallet fork and escapement wheel made from gold

Movement and components hand-finished and decorated


Hours and minutes

Perpetual calendar

Big date display

Month indicator via central hand

Seconds dial at 6 o'clock

Power reserve indicator at 9 o’clock

Leap year cycle indicator on movement side


Hand-stitched grey kudu leather

Steel folding clasp, engraved with the Moser logo