Here’s the thing about complicated watches: they draw power from the same barrel that feeds the escapement. This disrupts the regular and constant supply that is required by the meticulously adjusted escapement to fulfil its timekeeping function as precisely as possible. Jaeger-LeCoultre had worked on the solution to this problem in the early 2000s, which culminated in the invention of the Duometre mechanism in 2007. Patented by the brand, it features two separate barrels and two independent gear trains – one to drive the escapement (for timekeeping) and one to power the complications – both integrated into a single calibre and linked to a single escapement. This way, neither the escapement nor the complications can perturb the other. And of course, the first application of the Duometre concept in 2007 had to be a chronograph wristwatch due to the complications notorious need for short bursts of high power. Since then, there have been several more applications of the Duometre mechanism involving moon phases, travel time, and the tourbillon.
Jaeger-LeCoultre Duometre Chronograph Moon
This year, at Watches & Wonders Geneva 2024, the manufacture has added not one, but two brand new models to arguably its most underrated collection – one of which is the Duometre Chronograph Moon. Here, we bring you the details and our honest thoughts on Jaeger-LeCoultre’s latest Duometre masterpiece.
The Case, Dial, and Hands
This year marks the launch of a new case design for the Duometre, taking inspiriation from savonette pocket watches crafted by the Maison in the 19th century. With its convex crystal and rounded bezel, the case does indeed resemble a bar of soap (hence savonette). The crown also has been redesigned with deep and rounded notches. Easy on the eyes and to the touch, the new neo-vintage profile of the case is infinitely more charming than what it was previously, at least in our opinion. The case measures 42.5 mm in diameter – 0.5 mm larger than that of the regular Chronograph model – and is fitted with screwed lugs, rather than integrated ones. It is decorated with alternating polished, brushed, and micro-blasted (on the lugs) finishes, allowing for some stunning interactions with incident light. The Duometre Chronograph Moon is currently available in either pink gold or platinum.
The overall design of the dial remains fairly unchanged, once again featuring the distinctive three-counter layout and long, thin hands. The main dial and centre of each sub-dial have an opaline finish while the tracks surrounding the sub-dials are adorned with a concentric guilloched pattern. These sub-dials are sunken relative to the main dial, while the edge of the dial is curved, following the contours of the box crystal. Simple and effective, these design elements give the dial added depth and contribute to the neo-vintage flair of the watch.
Despite the many functions of the Duometre Chronograph Moon, its displays are intuitively laid out and relatively legible. The 10 o’clock sub-dial indicates the time in hours and minutes, and houses the new day/night indicator. Meanwhile, the 2 o’clock sub-dial displays the chronograph hours and minutes, as well as the phases of the moon. The 6 o’clock sub-dial, as always, is reserved for the foudroyante display. Two cut-outs next to it reveal the movement behind, along with the power reserve indicators (one for timekeeping, the other for complications). Running seconds as well as chronograph seconds are indicated centrally with both the seconds and tachymetre scale printed around the periphery of the dial.
The Movement
Driving the new Duometre Chronograph Moon is the equally new Jaeger-LeCoultre Calibre 391. The movement is fully integrated, combining a monopusher chronograph with moon phase and day/night complications, as well as two power reserve indicators and a foudroyante. The foudroyante starts and stops alongside the chronograph, superfluously allowing a reading accurate to 1/6th of a second. Each barrel – which drives its own independent gear train – has a power reserve of 50 hours.
The Duometre collection typically enjoys a higher level of movement finishing by the brand – closer to that seen in Master Grande Tradition watch movements than, say, entry level Master Control pieces. An array of bridges appear to be floating above levers and wheels. These bridges are decorated with sunrayed Geneva stripes which are challenging to execute because the parts must be decorated individually, and yet the pattern must radiate from the centre of the regulating organ to the edge of the calibre in perfect alignment once the parts are assembled. The edges of these bridges are also crisply bevelled and polished while the mainplate is decorated with even perlage. Heat-blued screws add a welcomed touch of colour to an otherwise silvery movement.
The Competitive Landscape
It’s not often you come across a chronograph watch combined with a (stand-alone) moon phase display. The two complications measure vastly different passages of time. One is also considered sporty, while the other, poetic. You would think that the combination is jarring but then comes along the Duometre Chronograph Moon to allay those concerns. After all, the main function of a watch is to measure time, and the Duometre Chronograph Moon does this excellently, measuring its passage both short and long, and everything in between. At the time of writing, only two variations of the model are available: pink gold with silver opaline dial, and platinum with copper dial. Both versions are part of the regular Duometre collection with the former priced at EUR79,000 and the latter at EUR97,000.
If the Duometre Chronograph Moon has got too much going on for your liking, then look no further than its older sibling, the Duometre Quantieme Lunaire. Lacking a chronograph and day/night indicator while gaining a date display, the Duometre Quantieme Lunaire has a noticeably cleaner dial. Despite the absence of a chronograph function, the watch still measures time as short as 1/6th of a second to as long as a lunar month. The latest iteration of the Duometre Quantieme Lunaire was released alongside the Chronograph Moon during Watches & Wonders Geneva 2024. Rendered in stainless steel (a first for the collection) with a blue dial, the watch is priced at around the USD44,000 mark.
While the chronograph/moon phase combination is uncommon, chronograph watches with full calendar complications inclusive of moon phase – especially the perpetual calendar – are popular and coveted in fine watchmaking. These watches are a different animal, but if the chronograph and moon phase complications are a non-negotiable, then something along the lines of the Master Control Chronograph Calendar should do the trick. Being a calendar watch, pragmatic functions like day, date and month are also part of the parcel. It has a classic dial layout, no foudroyante, no skeletonisation, and an attractive-albeit-entry-level movement finissage. The best bit about the watch, rendered in stainless steel, is that it is competitively priced at under USD20,000
Concluding Thoughts
The Duometre Chronograph Moon is the fruit of savvy watchmaking and design by Jaeger-LeCoultre, culminated from decades of experience and knowledge. Still, it isn’t going to be for everyone. It is substantial on the average wrist, has an eccentric dial design (smiley face, anyone?), and is just busy – factors that may put some off. That said, credit should be given where it is due. The new case is historically inspired, visually appealing, and significantly more nuanced in craftsmanship, and is therefore an objective improvement compared to the old. Connoisseurs will also appreciate that the movement is “built from scratch” and not merely a tinkered Calibre 380. Expect more fascinating variations to arise in the coming years.
