Considered the most legible and easy to set on the market, as it can be adjusted both forwards and backwards at any time of day, the iconic perpetul calendar timepiece makes a comeback in 2023, featuring 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.

Tantalum was discovered in 1802 by Swede Anders Gustav Ekeberg, and it it known as extremely dense and strong metal. 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. In contact with air, tantalum surfaces develop a fine layer of oxidation protecting the metal against aggression. The exquisite metal also offers anti-corrosive properties, and does not react with most chemical agents or dissolve in acid. Extremely malleable, tantalum is both hard and ductile, making it easily drawn out and worked with precision and finesse. Exceptionally stable, 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”. – Edouard Meylan, CEO of H. Moser & Cie

The perpetual calendar by H. Moser & Cie. is known for its complex movement. The absence of a subdial and date disc makes it very easy to read. The new version also removes 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. Each dial is unique. 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.

The finish is also remarkable, 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. 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.

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