Many watch enthusiasts accept without question the apex of the Perpetual Calendar complication as the peak of the complicated movement food chain. Quite simply, the perpetual calendar algorithm is a mathematical calculation that would prove mentally incalculable save for the intellectual prime of the human race. Defined, a perpetual calendar calculates a 400 year cycle with a break down of 303 common and 97 leap years, keeping tack of exactly 146,097 days. Mathematically, this task seems simple enough but throw in the 2nd month of the year and the variable length of February throws all but the most gifted among us for a loop.

Calendrier Chinois Traditionnel Calibre 3638

Are you convinced that it’s already quite difficult to build a perpetual calendar out of a collection of gears and wheels? Ok, let’s meet Blancpain’s Calendrier Chinois Traditionnel.

# The Calendrier Chinois Traditionnel

The Chinois Traditionnel works on one of the most complex calendar systems ever invented by humanity. Even native Chinese would be hardplaced to tell you which dates traditional East Asian holidays like Chinese New Year, the Duan Wu and Mid-Autmun Festival fall on each year (myself, I depend on relatives and Feng Shui advisors to do the calculation for me)

The month of the Chinese calendar )12 month cycle), its date (30 day cycle) and the leap month indicator appears at 9 o’clock. The Gergorian solar calendar uses the solar day as the base unit where the traditional Chinese calendar is a luni-solar calendar using a solar calendar with lunar cycle (29.5 days) as a base unit.

## Gregorian Vs. Chinese Calendar

Speaking with Priscilla Wee, marketing manager for Blancpain, she explains: In a traditional Chinese calendar, the calculation for days is based on lunar cycle between new moons in the principal part of the calendar. Despite the fact that a new moon cycles averages 29.53 days, it also can vary by several hours for any given time of the year. Since each month starts on the day of the new moon and the cycle is not an even number of days, a month in the lunar calendar can vary between 29 and 30 days and a normal year can be 353, 354, or 355 days. Hence the leap month or intercalary month, which appears every 2-3 years, is based on using calculations of lunar phases. On the contrary, the Gregorian calendar calculations are based on solar units, which will be more straight-forward, to determine the discrepancies of days lost by compensating an additional day in every 4 years.

Non-Asians (that is to say, the anglo-saxon watchmakers) have to understand the concept behind sexagenary cycle; and how the Chinese calendar corresponds to the Western (Gregorian) calendar.

12 o’clock features the zodiac sign of the year in progress while 3 o’clock shows the elements and the heavenly stems (10 year cycle). The combination of 10 heavenly stems and the 12 earthly branches gives the 60 year cycle allowing the wearer to keep track of years, months, days and hours in the Chinese calendar.

Next consider that they have to interpret all the information on a dial (the zodiac signs, double hour markers, additional reading for Chinese dates, five elements and ten celestial stems and leap month- yes you read that right); and then figure out how to fit all the complex parts with additional wheels for indication in the case, and yet maintaining its long power reserves of 168 hours (7 days) and you have the horological equivalent of re-interpreting Newton and creating a new Theory of Relativity.

The dial at 12 indicates the double-hour numerals and symbols (24 hour cycle). While we currently use the 24 hour a day system with each hour divided into 60 minutes, the traditional chinese system uses a 12 double hour system. Each double hour divides into 120 minutes.

## Calendrier Chinois Calibre 3638

The new self winding Calibre 3638 runs on a 7 day power reserve with 434 parts and 39 jewels as a result of the irregular nature of Chinese lunar cycles- the 45 mm platinum case accented with a cabochon-cut ruby crown with 5 under-lug corrects to adjust the dial indicators. All in all, despite the “information overload”, the watch face never looks cluttered and continues on the signature features of the Villeret collection- grand feu enamel dial with gold appliques chapter ring- the main hands as usual, are shaped like hollowed leaves while the blued steel date pointer adds subtle analogy with serpentine hand. Turn it over and the visible dragon engraving on oscillating weight completes the perception that this most Chinois of timepieces is not some gaudy over designed luxury watch but rather a well though out distinguished timepiece.

## Blancpain Causeway Bay, Hong Kong

(From left to right) Mr. Chiu Tsang Hei, Renowned Music Producer, Ms. Sincere Chiu, Vice President of Blancpain, Hong Kong and Macau, Mr. Marc Junod, Vice President Head of Sales, Blancpain SA, Mrs. Rita Hämmerli-Weschke, Consul General of Switzerland in Hong Kong, Mr.Kevin Rollenhagen, Managing Director of the Swatch Group (HK) Limited, Mr. Lionel a Marca, Vice President Head of Technical and Development Management, Blancpain SA, and Miss Linda Chung, Renowned Actress

Blancpain recently celebrated the grand opening of a boutique in Causeway Bay, Hong Kong with the flagship Villeret Traditional Chinese Calendar wristwatch on display on 12th September 2012. You can visit the boutique at 26 Russell Street, Causeway Bay.