Blancpain Villeret Equation du Temps Marchante (Running Equation of Time)

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Swiss watch manufacture Blancpain is a pioneer and the industry leader in the development of the running equation of time (équation du temps marchante) complication in wristwatches. The Le Brassus Equation du Temps Marchante, introduced in 2004 as a part of Le Brassus line, was a perfect example for the brand’s know- how in the field of running equation of time watches. In 2011, a new Running equation of time complication is introduced in Villeret Collection.
Equation of time has been one of the rarest wristwatch complications. Since it is expressing a value that changes over the course of the year, it has with the fewest of exceptions only appeared in timepieces offering perpetual calendars. This is a natural pairing as it brings together two complications that take account of yearly variances–equation of time, tracking the changes in the length of the solar day, and the perpetual calendar, keeping track of the varying length of months.

Until 2004, all wristwatch equation of time models offered only a plus-minus expression of the equation of time. That is they offered values such as “plus 14” or “minus 10” without indicating whether the conversion was from civil time to solar time or the reverse. It was left up to the owner of the watch to sort out that vital detail.

In 2004, Blancpain introduced its Le Brassus Equation du Temps Marchante, a world pioneer wristwatch that not only displayed a plus-minus expression of equation of time, but a running equation of time minute hand which directly showed solar time. No longer was it a mystery, left to the owner to decipher, whether the equation reading was converting from civil to solar or instead from solar to civil. Instead, Blancpain’s pioneering Equation du Temps Marchante showed two minute hands, one for civil and one for solar (the solar hand bearing a sun) so that the owner could directly read both times.

Take for example the date of September 22 shown on the perpetual calendar display in the photo of the red gold version of the Villeret Equation du Temps Marchante. On this date, the running equation of time solar hand shows that solar time is approximately 8 minutes ahead of civil time and the equation scale at 2 o’clock shows +8 minutes.

The marchante mechanism (running equation of time complication) is made by incorporing movement of the watch and an ellipsoidal cam in the shape of the anelemne which turns once a year. As that anelemne turns, a finger (or ratchet) riding upon it will move (or be programmed) according to the changes in the length of solar days which the anelemne shaped ellipsoidal cam expresses. This is the classic way in which conventional, less complicated equation of time displays have been constructed for over 200 years. The trick is devising a method to have the solar hand both move as a conventional minute hand and an equation of time hand.

It is necessary to have two different sources of rotation for the marchante solar hand and neither can interfere with the other, other wise the watch would not function. The ellipsoidal cam can be easily identified as can the finger which rides on it. The lever attached to the finger drives two separate mechanisms: one for the indication at 2 o’clock, which shows the +/– indication and the other the marchante hand. The secret is the gear in the marchante train labeled “differential”. That is not one single gear, but an entire differential mechanism which contains small satellite gears within it. It is the component which is driven from two different sources— one drives a gear which drives the satellites (the marchant train) and the other which drives the main exterior gear component (the watch’s minute train). The satellite gears can move freely forward and backwards without disturbing the movement of the minute hand and the minute hand train.

This movement which achieved a watchmaking first in 2004 (in the Le Brassus series which was a limited edition that sold out immediately) has now been reborn in the new Villeret Collection. As was the case with its 2004 Le Brassus predecessor, the new Villeret Equation du Temps Marchante places itself on the highest levels of watchmaking complication as it offers a full perpetual calendar, retrograde moon-phase display, and two equation of time indications (one on a +/– scale and the other with a running solar hand. The Villeret Equation du Temps Marchante is available in limited editions in platinum and red gold versions.
To further mark the exclusivity of this piece, the dial is fashioned in full fired bombé enamel. One element of the dial’s design is unique, the porthole at six o’clock. It offers a view of the equation of time cam and the finger which rides upon it.

Since the debut of the first equation of time watch, Blancpain has introduced its patented correctors under the lugs. Whereas others in the industry offering complicated calendar/moon-phase displays are obliged to fit correctors into small dimples on the sides of the case for the setting of the indications, Blancpain’s patented correctors are located where they are not a visible intrusion, under the case lugs. This allows the watch to have not only a completely clean side profile, unmarred by dimples, but for the owner to actuate the correctors with a finger tip instead of a tool which ordinary correctors require. The new Villeret Equation du Temps Marchante now incorporates this Blancpain exclusive innovation.

The Blancpain in-house savoir faire is on display in the new Villeret Equation du Temps Marchante. The visible movement bridges are all painstakingly hand carved into one of two designs: Universalis, which is a portrayal of the constellations, and Cartographia, a depiction of navigational charts, each further highlighted by hand-carved winding rotors maintaining the theme of the bridges. The Universalis design is reserved for the models in red gold, while the Cartographia design will be featured in the platinum models. A final finishing touch is the winding rotor, visible through the clear caseback. Realized in gold, the rotor is hand decorated with a solar pattern which includes special windows to frame the word “Blancpain” hand engraved on the bridge below.
Technical details
Models: Platinum (6638-3431-55B) & Red Gold (6638-3631-55B)
Features: VILLERET, Running Equation, perpetual calendar, retrograde moon phases, small seconds, white grand feu enamelled cambered dial, under-lug correctors, self-winding.

Movement
Calibre 3863
Thickness: 5,25 mm
Diameter: 26,80 mm
Power-reserve in hours: 72
Jewels: 39
Components: 397

Edition
Limited edition of: 88 Platinum (6638-3431-55B) & 188 Red Gold (6638-3631-55B)

Case
Platinum (6638-3431-55B) or Red Gold (6638-3631-55B)
Thickness: 11,50 mm Yes
Diameter: 42,00 mm
Water-resistance: 3 bar
Sapphire crystal back
Interhorn space: 23,00 mm

Strap
Alligator leather straps – origin: Mississippiensis