Since the launch of the Duometre Chronograph in 2007 —the first timepiece based on the ground- breaking Duometre concept— the system has been used with a few other complications, giving its name to a line of technically advanced watches that are distinguished by highly precise timekeeping. In 2024, Jaeger-LeCoultre presents a new generation of Duometre timepieces, among them a reinterpretation of the Duometre Quantieme Lunaire ref. Q604848J —Moon Phase. This is also the first Duometre piece to ever be offered in steel, its eye-catching blue dial, paired with a new case, lends a decidedly contemporary air to a timeless and distinctive design.

With their invention of the Duometre in 2007, Jaeger-LeCoultre’s engineers and watchmakers solved a fundamental problem of complex mechanical watches. That is, in order to operate, a complication must draw from the energy that is supplied from the barrel to the escapement via the gear train. This naturally interrupts the perfect regularity of the power supply and thus compromises precision.

In testament to the Maison’s inventiveness since its earliest days, its watchmakers had already explored solutions to the problem in the 19th century: in an 1881 pocket watch they introduced Calibre 19/20RMSMI equipped with two barrels. However, a double-barrel calibre still does not address the real issue because both barrels feed power to a single gear train that is employed for both timekeeping and the operation of complications.

Nevertheless, that early calibre provided the Manufacture’s 21st-century engineers and watchmakers with a starting point for the revolutionary Duometre concept. By effectively separating the power supply into two ‘streams’ – one barrel and gear train for timekeeping and a separate barrel and gear train for the complication(s), both linked to a single escapement —the Duometre system guarantees absolute constancy of the power supply, regardless of whether a complication is operating or not.

Emphasizing the precision of the calibre, a distinctive element of the Duometre Quantieme Lunaire dial is the seconde foudroyante hand, which whirls continuously in a sub-dial at 6 o’clock. Making a complete revolution in one second —versus a ‘standard’ seconds hand, which rotates in 60 seconds— with six ‘jumps’ per rotation, the foudroyante hand makes it possible to observe intervals of precisely one-sixth of a second.

On the deep blue dial of the Duometre Quantieme Lunaire, the long and very fine hands are a signature of all Duometre watches, as is the symmetrical layout, with three sub-dials forming an inverted pyramid. The sub-dial at 3 o’clock shows the time, with the cardinal hours marked by applied Arabic numerals; the sub-dial at 9 o’clock displays the date with a hand and the moon phase set against a blue sky. The seconde foudroyante sub-dial nestles beneath them at 6 o’clock.

The dial is made in several sections, with different finishes to create visual interest and contrast. The opaline main dial has the very soft glow and sense of visual depth characteristic of that decorative technique. The lower section of the dial is sunray-brushed and, in an added touch of refinement, the two power reserve indicators are distinguished from this sunrayed background by an opaline arc.

Inspired by the aesthetic of the sector dials that were featured on historic timepieces, the broad ring encircling each is sunray-brushed. The convex curve of the dial perimeter closely follows the contour of the glass -box crystal that protects it, and the sub-dials are slightly sunken into its surface, increasing the sense of visual depth.

Marking the launch of three new Duometre models in 2024, Jaeger-LeCoultre has designed an entirely new case for the collection. A contemporary interpretation of the savonette pocket watches created by the Maison in the 19th-century, its rounded contours are highly tactile as well as visually appealing. The French word savonette literally means a small disc of soap with rounded contours that can be cradled in the palm of a hand. With its convex crystal and gracefully rounded bezel, the new Duometre case expresses this literal definition very well. The crown, too, has been redesigned, with deep and rounded notches that make it a joy to handle. Indeed, the only sharp lines to be found are on the highly polished edges of the lugs.

A comfortable 42.5 mm in diameter, the case is a complex structure of 34 separate parts and the lugs are screwed rather than integrated, to enable multiple finishing techniques. A mixture of polished, brushed and micro-blasted surfaces creates a fascinating play of light with every movement of the wrist.

With its blue dial and steel case, the new interpretation of the Duometre Quantieme Lunaire lends a decidedly contemporary air to a technically sophisticated timepiece. It perfectly represents Jaeger- LeCoultre’s relentless pursuit of precision and its spirit of innovation, anchored in a deep respect for the traditions of Haute Horlogerie.

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