After pruning the perpetual calendar, H. Moser & Cie. doubles the passage of time in another pragmatic timepiece.
Dropping the oriental design with puzzling displays, the contemporary take on haute horlogerie has resulted in the Endeavour Chinese Calendar Limited Edition, which is easy to use and read despite the combined indications of the lunisolar and Gregorian systems.
Since there are no repeated cycles, the Chinese calendar posed a mechanical challenge for H. Moser & Cie., based in Neuhausen am Rheinfall in northeastern Switzerland.
The independent company founded by Heinrich Moser dates back to 1828. Today, under the "Very Rare" concept, it produces around 3,000 watches per year.
With 100 pieces available, the Endeavour Chinese Calendar Limited Edition is powered by the automatic in-house movement HMC 210, which is combined with a module developed by Geneva-based Agenhor SA.
The ingenious model shows precise indications of the lunisolar calendar for every 12 years without any corrections.
Calendars fundamentally replicate astronomical cycles based on observation of heavenly bodies sweeping across the sky.
Red gold Endeavour Chinese Calendar Limited Edition.
HMC 210 automatic calibre.
While the Gregorian calendar is based on the Earth's rotation around the Sun, the Chinese calendar tracks the cycles of the Moon while taking the Sun into account at the same time.
The ancient lunisolar system allows for scheduling agricultural activities, religious practices and social life. For instance, the Chinese New Year falls on a different date each year, and in 2024, the Year of the Dragon will begin on Feb 10.
Accordingly, the zodiac symbol will change from a rabbit to the dragon in an aperture at 12 o'clock on the Endeavour Chinese Calendar Limited Edition housed in a 40mm red gold case.
Elements of the solar and lunar calendars are calculated separately, and synchronised in the user-friendly model with a Midnight Blue fumé dial.
At 6 o'clock, the Gregorian date appears underneath the small seconds sub dial.
On the left, a crescent-shaped window indicates the lunisolar months while another one on the right simultaneously displays the days and the Moon phase.
Two retrograde hands with rounded tips travel along these apertures and return to their starting points once they have completed their course.
Based on the lunar cycle, Chinese months have 29 or 30 days, keeping in line with the phases of the Moon, which takes 29.53 days to orbit the Earth.
The 12 months of the lunar year last an average of 354.36 days which is 10.89 days fewer than a solar year of 365.25 days.
In a solely lunar calendar, the months shift with respect to the seasons, each month starting around 11 days earlier with every subsequent solar year.
To avoid an excessive discrepancy with the solar year, lunisolar calendars have a 13th month every two to three years.
These months are known as "embolismic" and are added to keep the lunar years aligned with the four seasons.
At 12 o'clock, two windows show the animal symbol of the lunisolar year and the embolismic month number whenever there is a 13 month year. In a standard 12 month year, this corresponding window will stay black.
H. Moser & Cie. noted that other Chinese calendars on the market require at least 70 manual corrections over a duodecimal period while the Endeavour Chinese Calendar Limited Edition operates according to the same cycle without external intervention.
This technical feat is made possible by two cams that work in parallel and convey information on the number and duration of the Chinese months.
At the end of the 12 year period, the cams are simply changed for the next cycle when the watch is serviced.
