• New platinum 950 bracelet:  extending the timepiece’s refined monochrome aesthetic

• An innovative tourbillon: triple-axis construction creates a unique kinematic effect and enhances precision

• Calibre 388: allies the Duometre concept to a perpetual calendar with Grande Date display

• An exclusive production: each timepiece is part of a highly exclusive limited production of just 20 pieces

In 2024, Jaeger-LeCoultre created the Duometre Heliotourbillon Perpetual, uniting two lines of expertise in high-precision timekeeping – the Duometre concept and a novel form of multi-axis tourbillon – to create Calibre 388. Now, it reinterprets this highly sophisticated perpetual calendar timepiece in platinum, with a new case and matching bracelet complemented by a grey dial. It will be produced in a limited and numbered edition of 20 pieces.

A MONOCHROMATIC PALETTE CREATES AESTHETIC HARMONY

Crafted in platinum for this new model, the 44 mm Duometre case is a contemporary interpretation of the savonette pocket watches created by Jaeger-LeCoultre in the 19^th-century. Its rounded contours, amplified by the convex crystal, polished bezel and deeply notched winding crown are highly tactile as well as visually appealing. The apparent simplicity of the case belies its complexity: it comprises 40 separate parts and the lugs are screwed rather than integrated, to enable a mixture of polished, brushed and micro-blasted surfaces that play with shadows and reflections as every movement of the wrist captures the light differently.

Created specifically for this reinterpretation of the Duometre Heliotourbillon Perpetual, the new platinum 950 bracelet combines technical sophistication with refined elegance. Its supple five-row construction ensures exceptional comfort on the wrist, while alternating brushed and polished finishes echo the meticulous finishing of the case. Inspired by the vintage design codes of the Duometre collection, the bracelet’s fluid integration enhances the distinctive rounded silhouette of the case. Each link is individually domed along the 12 o’clock to 6 o’clock axis – subtly recalling the curvature of the lugs – and carefully brushed and bevelled on both sides to create a sophisticated interplay of light.

Harmonising with the cool silvery tones of the platinum case and bracelet, the new all-grey dial is finished in a mix of opaline, brushed and azuré surfaces, creating subtle contrasts between the different indications. The curving platinum bridge that separates the displays from the tourbillon aperture is finished with microblasting and bevelling. In contrast, the polished hands, applied hour markers and frames surrounding the date display create a subtle interplay of light.

Directly expressing the underlying Duometre mechanism, with its two barrels and gear trains, the symmetrical dial layout of the Duometre Heliotourbillon Perpetual forms a triangle, with its apex defined by the grande date display at 3 o’clock.  The two power reserves sit above and below the time display. The ‘base’ of the triangle is formed by the display of moon-phases and days in the upper sector, and the perpetual calendar’s months and years in the lower part.

On the left-hand side of the dial, the triple-axis tourbillon performs its ‘spinning top’ rotation and a sapphire crystal window in the side of the case offers another view of its mechanical dance. The tourbillon is set above a background of deep blue lacquer representing a starry sky and, as it spins, red triangles set on the third cage indicate 20-second intervals, which are marked on a sapphire crystal arc.

BREAKTHROUGHS IN PRECISION: THE HELIOTOURBILLON AND THE DUOMETRE CONCEPT

Incorporating Jaeger-LeCoultre’s eight decades of accumulated expertise in the tourbillon regulating mechanism, Calibre 388 features a distinctive tourbillon construction that spins on three axes, enhancing chronometry and creating a kinematic effect that resembles a spinning top.

As it spins on a single axis, the traditional tourbillon does not compensate for the effects of gravity in all positions, which led the Manufacture’s engineers to develop different configurations, including the signature dual-axis Gyrotourbillon. The Heliotourbillon takes this thinking further, with three titanium cages rotating on three axes and a cylindrical hairspring. The first cage is set at a 90-degree angle to the balance wheel and the second cage is set at 90 degrees to the first. Together, these two cages are driven and constrained by an axis tilted at 40 degrees which makes a full rotation in 30 seconds. The third cage is perpendicular to the second and makes a full rotation in 60 seconds.  Supported on ceramic ball bearings to minimise friction, the tourbillon consists of 163 components and weighs less than 0.7 grams. 

Before Jaeger-LeCoultre developed the Duometre concept, adding complications to a watch movement seemed irreconcilable with accurate timekeeping. That’s because the fundamental requirement of precise timekeeping is that the power supply from the barrel to the escapement should never vary. However, a complication must draw on the power supply to operate, thus interrupting that steady flow and jeopardising precision. Introduced in 2007, the patented Duometre mechanism features two barrels and two separate gear trains housed in a single calibre and linked to a single regulating organ. One gear train powers the time indications and the other drives all additional functions. By separating the power supply in this way, the Duometre mechanism guarantees an exceptionally high degree of operating accuracy.

A PERPETUAL CALENDAR WITH A GRANDE DATE DISPLAY

Complementing the sophistication of the tourbillon and Duometre mechanisms, Jaeger-LeCoultre’s watchmakers integrated a perpetual calendar into Calibre 388. Automatically adjusting for months of different lengths and for leap years, it needs no manual correction until 2100 and subsequently only in centenary years that are not also leap years. The year indication shows the last digit of a leap year in red – a Jaeger-LeCoultre patent. Unusually, in Calibre 388 the hours and minutes can be set either backwards or forwards without compromising the perpetual calendar. Normally, a perpetual calendar is set through the passing of time (the hour and minute hands), so adjusting the time backwards desynchronises and can damage the calendar mechanism. Calibre 388 also includes a Grande Date display: a classical yet rare complication sought-after by watch connoisseurs, and a moon-phase indication accurate to 122 years.

Calibre 388 features fine decoration, even on components that are not visible through the sapphire crystal caseback: brushed surfaces contrast with perlage; edges are hand-bevelled and polished; sunrayed Geneva stripes (côtes de Genève soleillées) radiate seamlessly across the expanse of the bridges. Like all Jaeger-LeCoultre movements, Calibre 388 was conceived, designed, produced, assembled and finished within the Manufacture.

Complex, highly innovative and aesthetically refined, the Duometre Heliotourbillon Perpetual in platinum epitomises Jaeger-LeCoultre’s boundless creativity and its technical sophistication represents a new achievement in the Maison’s quest for timekeeping precision.

TECHNICAL CHARACTERISTICS

DUOMETRE HELIOTOURBILLON PERPETUAL

Case: Platinum 950/1’000

Dimensions: 44 mm x 14.7 mm thick

Calibre: Manually wound Jaeger-LeCoultre Calibre 388

Functions: Hours and Minutes, Seconds, Heliotourbillon, Perpetual calendar (Day, Date, Month, Year), Moon phases, two power reserves

Power Reserve: 46 hours for each barrel

Front dial: Anthracite grey with opaline, brushed and azuré finishes

Water resistance: 3 bar

Strap: Platinum 5-row bracelet with white gold 750/1’000 clasp

Reference: Q6206150 – limited edition of 20 pieces

• The new Calibre 391 unites a highly complex chronograph with a moon phase display
• The patented Duometre mechanism ensures remarkable precision
• A new case and dials express contemporary elegance in distinctive style

In 2007 Jaeger-LeCoultre launched the ground-breaking Duometre mechanism in the form of a chronograph – the complication that epitomises the concept of precision. In 2024, the Maison applies the Duometre concept in an entirely new timepiece, marrying the high precision of a chronograph with the charm of a celestial complication. Powered by the new Calibre 391, the Duometre Chronograph Moon presents an intriguing contrast between the lightning-fast operation of the chronograph – which can time intervals as small as 1/6^th of a second – and the slow rhythm of the moon as it passes through its cycle in 29.53 days, complemented by a Night and Day display.

At Watches and Wonders 2024, Jaeger-LeCoultre presents the Duometre Chronograph Moon in two variations: a platinum case contrasting with a copper-coloured dial, and a pink gold case offset by the discreet elegance of a silver dial. Both models are enhanced by a hand-stitched alligator strap with small-scale alligator lining.

Solving the Conundrum of Complications

The fundamental problem of complex mechanical watches is that, for any complication to operate, it naturally draws on some of the power provided by the barrel. This disrupts the perfectly regular and constant supply that is required by the meticulously adjusted escapement to fulfil its timekeeping function as precisely as possible.

The search for a solution to this problem at Jaeger-LeCoultre during the early 2000s eventually led to the invention of the Duometre mechanism. Introduced in 2007 and patented by Jaeger-LeCoultre, 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. For the first time, it was possible to guarantee that the movement’s isochronism (the regularity of its ‘heartbeat’) is not compromised by the operation of any complication.

While the Duometre is revolutionary in modern watchmaking, the underlying principle had, in fact, been explored by the Manufacture more than 120 years earlier; the LeCoultre Calibre 19/20RMSMI was equipped with two barrels and fitted into a pocket watch in 1881. Because that calibre had only one gear train, it did not solve the fundamental problem; nevertheless, it provided a theoretical ‘trigger’ for the Duometre concept.

Jaeger-LeCoultre’s engineers and watchmakers chose the chronograph for the first application of the Duometre concept in 2007 as it represented the greatest challenge to accurate timekeeping posed by any complication because its operation requires short bursts of very high power. Since then, the Duometre mechanism has been associated with several other complications, including moon phases, travel time and a tourbillon.

An Entirely New Calibre

For Calibre 391, Jaeger-LeCoultre’s engineers started from the ground up to develop a fully integrated movement that combines a manually wound mono-pusher chronograph with moon phase and night-day complications, as well as two power reserve indicators and a seconde foudroyante (flying second) display.

When the chronograph mechanism is activated, the foudroyante hand begins its whirling dance, making a complete rotation in one second, during which it beats six times – stopping instantaneously when the chronograph timer is stopped and thus providing a reading accurate to 1/6^th of a second.

On the dial side of the Duometre Chronograph Moon, two open-worked sections offer intriguing glimpses of the mechanism, hinting at the mechanical beauty of the calibre. On the reverse side, fully revealed beneath the transparent crystal case-back, much of the movement is open-worked and an array of bridges seems almost to be floating above the levers and wheels, drawing the eye deep into the mechanism. Creating visual unity across the entire expanse of the movement, the bridges are decorated with sunrayed Geneva stripes. It’s a challenging technique that demands absolute precision because the components must be decorated one-by-one, and yet radiate from the centre of the regulating organ to the edge of the calibre in perfect alignment once the movement is assembled.

The open-working of Calibre 391 serves two purposes: not only does it greatly enhance the aesthetics, it also serves a technical purpose, enabling the watchmakers to more easily assemble some parts of this highly complex calibre. This is a fine example of Jaeger-LeCoultre’s philosophy of marrying mechanics and aesthetics in such a way that each serves the other. Being a manually wound calibre, there is no winding rotor to conceal the chronograph levers.

Traditional Haute Horlogerie finishes abound: crisply bevelled and polished angles define the edges of the bridges; brushed surfaces contrasts with polished metal; perlage on the main plate reflects light back up through the mechanism; and blue screws provide a pleasing contrast to the silvery tones of the metal.

A Fascinating Display and Refined Details

The dial is both elegant and intuitive to read, featuring the distinctive three-counter layout and long, thin hands that make the Duometre so recognisable. Echoing the aesthetic of traditional sector dials, the main dial surface and the centre of each sub-dial has the fine, almost powdery texture achieved by the opaline finish; in contrast, the broad ring encircling each sub-dial is decorated with azuré (ultra-fine engraving in perfectly regular, concentric circles). Adding to the visual appeal, the sub-dials are slightly sunken below the main surface, while the edge of the dial is subtly curved, closely following the contours of the glass box crystal.

Enhancing the symmetry of the layout, the moon phase display is integrated into the chronograph hours and minutes sub-dial, which is set at 3 o’clock. Its blue background is visually balanced by that of the Night and Day display, which is integrated into the time sub-dial at 9 o’clock. Elapsed time is displayed up to 12 hours, 60 minutes and 60 seconds, accurate to 1/6^th of a second and a tachymeter scale marked around the periphery of the dial enables the wearer to measure speed based on the time taken to travel a fixed distance, or to calculate distance based on speed.

The seconde foudroyante is displayed in a sub-dial at 6 o’clock, flanked by the two open-worked areas that reveal parts of the mechanism. The two power reserves (50 hours for each barrel and gear train) are displayed on an arc-shaped bridge on each side of the sub-dial. Both barrels are wound by a single crown – forwards for the barrel that provides power for the timekeeping function and backwards for the second barrel, which provides power for the complications.

A New Duometre Case: Contemporary Elegance Inspired by Tradition

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 19^th-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 highly polished edges of the lugs are the only sharp lines to be found.

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 the use of 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 an entirely new calibre, dial and case, the Duometre Chronograph Moon is an eloquent expression of Jaeger-LeCoultre’s relentlessly creative spirit. It embodies the Maison’s philosophy of combining beauty with technical sophistication, and a deep respect for the traditions of Haute Horlogerie with constant innovation – always with precision at the heart of the matter.

TECHNICAL CHARACTERISTICS

DUOMETRE CHRONOGRAPH MOON

Case: Pink Gold 750/1000 (18 carats) or 950 platinum

Dimensions: 42.5 mm diameter x 14.2 mm thick

Calibre: Manually wound Jaeger-LeCoultre Calibre 391

Functions: Hours, minutes, seconds; Chronograph with 12-hour counter, 60-minute counter, 1/6^th-second counter and central chronograph seconds; Moon phases, Night & Day, two Power Reserve indicators

Power Reserve: 50 hours for each barrel

Front dial:  Silver opaline (in pink gold case); Copper-coloured opaline (in platinum case)

Water resistance: 5 bar

Strap: Alligator with small scale alligator lining

Reference: Pink Gold: Q622252J / Platinum: Q622656J

• An innovative tourbillon constructed on three axes to create a unique kinematic effect – a first for Jaeger-LeCoultre 
• The Duometre concept allied to a perpetual calendar with a grande date 
• New manual Calibre 388 developed and produced in-house

Over the course of almost two centuries, Jaeger-LeCoultre has distinguished itself through the development of increasingly sophisticated means of achieving the perfect regularity of the ‘heartbeat’ of its calibres – essential for accurate timekeeping. Among the key areas of research in this pursuit of precision, the Manufacture has developed great expertise in tourbillons and also invented the Duometre mechanism, which enables the addition of complications without any compromise to the accuracy of the timekeeping function. 

In 2024, Jaeger-LeCoultre unites these two lines of development, to create the Duometre Heliotourbillon Perpetual. Pushing the boundaries of inventiveness further than ever, the new Calibre 388 features an entirely new tourbillon construction: one that spins on three axes to create a ‘spinning top’ effect. Beating at a frequency of 4Hz (28,800 vph) to further enhance chronometry, Calibre 388 also incorporates a perpetual calendar with a grande date indication.

The Duometre Concept – a Breakthrough in Precision 

Before Jaeger-LeCoultre developed the Duometre concept, adding complications to a watch movement seemed irreconcilable with accurate timekeeping. That is because the fundamental requirement of precise timekeeping is that the power supply from the movement’s barrel to the escapement should be absolutely steady. However, in order to operate, a complication must draw on the power supply, which interrupts that steady flow and thus jeopardises precision. 

Introduced in 2007, the patented Duometre mechanism features two barrels and two separate gear trains housed in a single calibre and linked to a single regulating organ. One gear train powers the time indications and the other drives all additional functions. By separating the power supply in this way, the Duometre mechanism guarantees an exceptionally high degree of operating accuracy. 

Thanks to this ingenious concept, the Manufacture Jaeger-LeCoultre added a new chapter to watchmaking history, opening the door to horological complexity and laying the foundation of an entire Duometre collection.

The Heliotourbillon – a New Spin on Multiple Axes

 
Incorporating almost eight decades of accumulated expertise in the tourbillon regulating mechanism, the Duometre Heliotourbillon Perpetual, features a newly developed tourbillon configuration that rotates on three axes. In doing so, it creates a completely new kinematic effect for Jaeger-LeCoultre resembling a spinning top. 

Initially devised for pocket-watches, the traditional tourbillon, which spins on a single axis, does not compensate for the effects of gravity in all positions. Having understood that an additional axis of rotation must be added in order to be more effective in all positions that a wrist-worn watch may adopt, Jaeger-LeCoultre’s engineers developed the dual-axis Gyrotourbillon, and various other tourbillon configurations, each fitted with differently shaped hairsprings. 

Fitted with a cylindrical hairspring, the Heliotourbillon takes this thinking further, with a newly developed construction comprising three titanium cages rotating on three axes. The first cage is set at a 90-degree angle to the balance wheel and rotates perpendicular to it. The second cage is set at 90 degrees to the first (thus, on the same plane as the balance wheel). Together, these two cages are constrained by an axis tilted at 40 degrees and make a full rotation in 30 seconds. The third cage is perpendicular to the second and makes a full rotation in 60 seconds. Supported on ceramic ball bearings to minimise friction, the tourbillon consists of 163 components and weighs less than 0.7 grams.

A Perpetual Calendar with a grande date Display 

As a noble complement to the highly sophisticated tourbillon and Duometre mechanisms, Jaeger-LeCoultre’s watchmakers integrated a perpetual calendar into Calibre 388. Among the most challenging complications to master, a perpetual calendar is a miniature mechanical computer that must automatically adjust for months of different lengths and for leap years; it needs manual correction of the day and date indications only in 2100 and in subsequent centenary years that are not also leap years. 

A feature of Calibre 388 is that the hours and minutes can be set either backwards or forwards without compromising the perpetual calendar. Because normally, a perpetual calendar is set through the passing of time (the hour and minute hands), adjusting the time backwards desynchronises and can damage the calendar mechanism. In Calibre 388, the relationship between the winding and calendar assemblies is such that the perpetual calendar mechanism moves forwards only and cannot be dragged backwards when the time is set backwards. 

Other notable features of Calibre 388 include a Grande Date display: a classical yet rare complication sought-after by watch connoisseurs, it is set at the 3 o’clock position on the hours-and-minutes sub-dial, ensuring great legibility. The year indication shows the last digit of a leap year in red – a Jaeger-LeCoultre patent – and the moon-phase indication is accurate to 122 years.

A Refined Dial Reinterprets the Duometre’s Aesthetic Codes 

The Duometre collection has always been distinguished by the powerful symmetry of the dial layout. On the dial of the Duometre Heliotourbillon Perpetual, the triangular arrangement that directly expresses the underlying mechanism with its two barrels and gear trains has been turned 90 degrees, as if the winding crown forms the apex of the triangle, the time display is flanked by the two power reserves, and the ‘base’ of the triangle is formed by the moon-phase indicator and days on one side and the months and years on the other. 

On the vertical axis, the two sides of the dial are separated by a gold bridge with contrasting areas of microblasting and bevelling, creating an intriguing play of light – and echoing the finishes on the watch case. The left-hand side of the dial is open-worked to provide a fascinating view of the tourbillon performing its ‘spinning top’ rotation – a kinematic effect created by the combination of the three cages rotating on different axes and at different speeds. A sapphire crystal window in the side of the case offers another way to view this captivating mechanical show. 

The tourbillon is set above a background of deep blue lacquer representing a starry sky and, as it spins, red triangles set on the third cage indicate 20-second intervals marked on a sapphire crystal arc that floats above the starry blue background. On the main dial refined finishes abound, with applied hour indexes and frames around the date and year, and a mix of opaline, brushed and azuré surfaces creating subtle contrasts between the different indications. 

Epitomising the noble art of watchmaking tradition, this fine decoration is carried over to the movement, even on components that are not visible through the sapphire crystal caseback: brushed surfaces contrast with perlage, edges are hand-bevelled and polished, and sunrayed Geneva stripes (côtes de Genève soleillées) radiate seamlessly across the entire expanse of the bridges. Like all Jaeger-LeCoultre movements, Calibre 388 was conceived, designed, produced, assembled and finished within the Manufacture.

A New Duometre Case: Contemporary Elegance Inspired by Tradition 

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. 

Measuring 44 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. The apparent simplicity of the case belies its complexity of detail, which perfectly complements the complexity of the calibre within. 

With its extreme mechanical sophistication, innovative tourbillon and highly refined aesthetics, the Duometre Heliotourbillon Perpetual represents a new adventure in the Maison’s quest for precision, as well as its boundless creativity.

TECHNICAL CHARACTERISTICS 

DUOMETRE HELIOTOURBILLON PERPETUAL 

Case: Pink Gold 750/1000 (18 carats) 
Dimensions: 44 mm x 14.7 mm thick 
Calibre: Manually-wound Jaeger-LeCoultre Calibre 388 
Functions: Hours and Minutes, Seconds, Heliotourbillon, Perpetual calendar (Day, Date, Month, Year), Moon phases, Two power reserves 
Power Reserve: 46 hours for each barrel 
Front dial: Silver opaline 
Water resistance: 3 bar 
Strap: Brown alligator leather with small-scale alligator lining 
Reference: Q6202420 – limited edition of 20 pieces