• Inviting the public to explore the story of fine watchmaking from the inside
• A new programme reveals the art and science of precision
• The Atelier d’Antoine initiative expands around the world

In line with Jaeger-LeCoultre’s 2024 theme – ‘The Precision Pioneer’ – The Atelier d’Antoine continues to enrich its programme of hands-on educational experiences. A new series of Discovery Workshops and Manufacture Visits takes participants on a journey of discovery that reveals the profound importance of precision in every aspect of fine watchmaking.

Sharing the Inside Story of Watchmaking with a Wider Audience

Named in honour of the Maison’s founder, the Atelier d’Antoine initiative is driven by Jaeger-LeCoultre’s commitment to sharing the art and science of watchmaking with wider audiences. Its themed programmes offer the general public – collectors, curious enthusiasts, and complete novices alike – an incredible opportunity to immerse themselves in the world of fine watchmaking.

The Discovery Workshops are a new way to discover the inside story of how fine Swiss watches are born and made. Hosted by an instructor and a technical expert from the Manufacture and limited to a maximum of eight participants, each workshop is dedicated to a specific theme and blends academic education and hands-on experience in a dynamic format that encourages constant interaction.

Participants have the option of deepening their knowledge by combining a Discovery Workshop with a guided Manufacture Visit focused on the same theme – a rare opportunity to explore the heart of a fully integrated watchmaking Manufacture.

A Deep Dive into the Fascinating World of Precision

In 2024, Jaeger-LeCoultre is pleased to announce a new programme to be offered by The Atelier d’Antoine.  Focusing on precision – a pillar of the Maison since it was founded in 1833 – this programme presents a great opportunity to discover why precision is crucially important at every stage of the watchmaking process.

As its name suggests, the ‘Precision Pioneer’ programme reveals the true meaning of precision in watchmaking, the challenges that mitigate against it, and the exceptional degree of skill required to achieve precision at the highest level. Rarely showcased in its own right, precision is fundamental to every stage of the watchmaking process from raw materials to finished timepieces. Participants in this Discovery Workshop will encounter many surprises:

• The powerful technology that transforms raw metal into micron-accurate shapes;
• The extraordinarily precise hand gestures involved in finishing components and assembling calibres;
• The rigorous testing processes to ensure the optimum performance of every watch;
• The discovery of the measuring tools – both historic and state-of-the-art – that the Manufacture’s engineers and watchmakers use every day;
• The opportunity to discover the mysteries of the tourbillon as never before.

The ‘Precision’ Manufacture Visit will take guests on a two-hour guided tour of the Jaeger-LeCoultre Manufacture, which includes several workshops that are rarely opened to visitors. Highlighting the exceptional value of being a fully integrated Manufacture, the visit will begin with an exploration of how the relentless pursuit of precision has changed the course of the Manufacture’s long history and, in some cases, of the watchmaking industry as a whole. It will lead guests through key points in the watchmaking journey from raw materials to finished timepieces – from industrial and technology-driven processes to the fine manual crafts of pre-assembly and the romance and magic of high complications – discovering areas of expertise that are normally hidden from public view.

Expanding the Atelier d’Antoine Initiative

The heart of the Atelier d’Antoine is a specially designed space within the original historic Manufacture building in the heart of Switzerland’s Vallée de Joux. In line with Jaeger-LeCoultre’s desire to welcome more people into the world of fine watchmaking, The Atelier d’Antoine is also expanding to other locations around the globe. Today, the flagship boutiques in Shanghai and New York incorporate an Atelier d’Antoine space dedicated to hosting the Discovery Workshops. Similarly, the new flagship boutiques in Dubai and Beijing – both due to open this year – will feature dedicated spaces. The new Precision Pioneer Discovery Workshop will be among the different themes presented at various times throughout the year. The Atelier d’Antoine also forms part of Jaeger-LeCoultre’s major travelling exhibitions, subject to the location.

Reservations for The Atelier d’Antoine can be made online at https://www.jaeger-lecoultre.com/atelier-antoine-discovery-workshops-precision-pioneer – where visitors can also discover more about The Atelier d’Antoine and the opportunities it offers. Bookings in New York can be made online or at the flagship boutique.

The new Atelier d’Antoine ‘Precision Pioneer’ programme will be an unforgettable experience for those wishing to learn more about what goes into creating a fine watch in the 21^st century.

Key dates:

• 1558: Pierre LeCoultre’s arrival in Switzerland
• 1612: Birth of Le Sentier village
• 1684: Blacksmiths pre-eminence
• 1749: Recognition of watchmaking

Since the dawn of history, when the notion of time was established through observation of the movement of the sun and moon across the sky, and the changing of the seasons, mankind has been on a quest to define and measure time more accurately. Over the millennia, a succession of devices has been invented – the sundials and water clocks of ancient Egypt, Babylon and Greece; Chinese incense clocks and medieval hourglasses and Islamic water clocks – each representing the pinnacle of accurate timekeeping in its era.

After the first mechanical clocks were invented in the mid-14^th century, the drive for precision gained pace. These new machines were capable of measuring time much more accurately and soon, the increasing sophistication of clockmaking technology opened the door to the development of portable timepieces – the smaller scale of which demanded ever greater precision in the shaping of components and the architecture and assembly of the movements.

At Jaeger-LeCoultre, the pursuit of precision has been a central tenet of the Maison since it was founded in 1833 by Antoine LeCoultre, an inventor and watchmaker for whom it was something of an obsession. His watchmaking atelier quickly built a reputation for outstanding quality and, as LeCoultre & Cie grew into a fully-fledged Manufacture, it set the standard for the entire industry. From the mid-1800s onwards, as its calibres were sought after by many of Switzerland’s greatest watchmaking houses for use in their own timepieces, the Maison became known as the Watchmaker of Watchmakers.

However, the roots of Jaeger-LeCoultre’s pursuit of precision lie in distant history; the story began more than 250 years before the Maison was founded and is intrinsically bound to the history of the Vallée de Joux itself.

Into Exile – 1558

From 1517 onwards, the Protestant Reformation spread from Germany and Switzerland into France and, as the movement grew, persecution of the Huguenot (French Protestant) minority became increasingly harsh. In 1558, fleeing that persecution, Pierre LeCoultre was among the refugees who made their way to Geneva, where the theologian John Calvin had established Protestantism as the city’s official religion. There, LeCoultre obtained the coveted status of ‘inhabitant’ of the City of Geneva.

At that time, merchants and financiers from Geneva had begun to exploit the Vallée de Joux’s natural resources of iron and timber – building forges, establishing logging businesses and beginning the metallurgy industry for which the valley was to become famous. No doubt Pierre LeCoultre heard stories about the Vallée, brought back from to the city by those early businessmen.

The birth of Le Sentier, Vallée de Joux – 1612

In 1559, driven by an entrepreneurial spirit and a taste for adventure and challenge, Pierre LeCoultre left Geneva for the Vallée de Joux.

Perched at an altitude of 1,000 metres with the only access being through passes often closed for months by heavy winter snow, the Vallée de Joux was a wild place of rocks and forests, governed by a harsh climate. To survive in the valley, patience, perseverance and probity were essential character traits that, over the generations, came to define the mentality of the Combiers (as inhabitants of the Vallée de Joux are known). Many generations later, this temperament was to make them ideally suited to the intricate craft of watchmaking.

Pierre LeCoultre obtained the rights to a plot of land, where he cleared the forest, built a home and made a farm. Despite the inhospitable environment, the long and cold winters and the extreme challenges of daily life, he managed to settle permanently and, thanks to his ability to read and write, became one of the notables of the Vallée. After he died, he was succeeded by his son, also named Pierre.

In 1612 – with the blessing of the Protestant city of Bern, which then had authority over the Vallée de Joux – the junior Pierre built a chapel in Le Sentier, which marked the birth of the village that became Jaeger-LeCoultre’s home.

From Disaster to Blacksmithing Pre-eminence – 1684

With the Vallée’s fortunes dependent on the forges – and the felling of timber to power them – a devastating forest fire in 1613 wiped out much of the traditional economy. While the forges could continue operating with coal imported from outside the Vallée, those who had relied on logging and selling wood were forced to develop other sources of income. Small, artisanal enterprises began producing furniture, clothing and metal tools – testament to the Combiers’ resilience and spirit of self-reliance. In addition, some began to produce wooden clocks inspired by models that had been introduced to the Vallée from Geneva.

Increasingly, farmers installed their own domestic forges and blacksmithing provided a reliable second source of income. With a taste for precision and meticulous attention to detail, the blacksmiths began to specialise in small items such as blades, buckles, locks and handles; confined to their houses during the long and freezing winter months, they had ample time to hone their skills. For the metallurgy trades of the Vallée de Joux, 1684 was a milestone, marking the official end of a long period during which Genevan businessmen had held legal rights over these activities. By the end of the 17^th century, the blacksmiths and other artisans of the Vallée de Joux enjoyed a reputation for quality that spread far beyond their own region.

Official Recognition of Vallée de Joux Watchmaking – 1749 

Encouraged by the official recognition of watchmaking as a profession in 1723, and burgeoning public interest in horology (although only the very wealthy could aspire to owning a timepiece) a growing number of the Vallée’s craftsmen leveraged their remarkable metal-working skills to learn the watchmaking trade.

In 1749, Bern officially granted commercial and industrial autonomy to the artisans of the Vallée de Joux and, as the number of apprentice watchmakers from the Vallée multiplied, the reputation of the master craftsmen grew, especially in Geneva where their products were increasingly sold. In the latter part of the century, in parallel with growing interest in watchmaking throughout Europe, music boxes surged in popularity, encouraging many of the blacksmith-craftsmen to specialise in music box components. Among them was Antione LeCoultre’s father, Jacques-David.

Ten generations after Pierre LeCoultre had arrived in the Vallée de Joux, 16-year-old Antoine LeCoultre joined his father in the small family forge and began learning the mysteries of metallurgy. In 1823, the LeCoultres began producing razors of an exceptionally well hardened (quenched) steel and subsequently designed a watchmaking chisel benefiting from the same quenching method. They developed new alloys, laid the foundations of the razor industry, and perfected the pins and vibrating blades of music boxes.

Founding of the LeCoultre Watchmaking Atelier – 1833

Switzerland’s liberal revolution of December 1830 – which, among other benefits, guaranteed the freedom of commerce – encouraged entrepreneurs in the Vallée de Joux to embark on artisanal and industrial adventures.

 Obsessed with precision, in 1830, Antoine LeCoultre, a self-taught watchmaker, had already invented a machine for cutting pinions from steel and went on to develop precisely calibrated cutting and stamping machines that could measure and cut components more accurately and on a smaller scale than ever before.

Obsessed with precision, in 1830, Antoine LeCoultre, a self-taught watchmaker, had already invented a machine for cutting pinions from steel and went on to develop precisely calibrated cutting and stamping machines that could measure and cut components more accurately and on a smaller scale than ever before.

Building on the foundation of this new invention, Antoine LeCoultre transformed the first floor of the family forge in Le Sentier into a watchmaking atelier in 1833. By grouping together a handful of watchmakers, he began creating timepieces of great accuracy, marking the debut of a long series of production that continues to this day.

Once the pinion-cutting machine was invented and the production set in motion, Antoine LeCoultre was determined to ensure that his artisanal methods were of the highest quality. To guarantee the excellence of his produced components, he invented the Millionometre in 1844, which made it possible not only to measure components with an unprecedented level of precision, but also to miniaturise them even further.

By enabling the measurement and reproduction of parts with absolute precision, Antoine LeCoultre freed watchmaking from the constraint of producing timepieces one-by-one, thus laying the foundations of the modern watchmaking industry.

The Unrelenting Pursuit of Precision – from 1844 onwards

In 1851, Antoine LeCoultre displayed his inventions at the Great Exhibition in London – the first World’s Fair – and was rewarded with a gold medal, particularly for his pioneering role in the field of component interchangeability. The first international recognition of his work, this contributed to the Swiss watchmaking industry’s eventual preeminence over its English counterpart.

By enabling the miniaturisation of parts without sacrificing timekeeping accuracy, LeCoultre’s inventions made it possible to develop watches of ever smaller size and greater complexity – chronographs, calendars and chiming watches. As these calibres were highly sought after by the leading watchmaking houses for use in their own timepieces, the Maison became known as the Watchmaker of Watchmakers – and the Vallée de Joux became known as the cradle of complications.

In 1866, Antoine LeCoultre and his son Elie established the first fully-fledged Manufacture in the Vallée de Joux, uniting all the watchmaking crafts under one roof. At a time when watchmaking was based on the principle of établissage – an ecosystem of small workshops each owned by a specialist in one of the crafts – it was a prescient move that, by encouraging the closer exchange of ideas and enabling series production, came to define the modern watchmaking industry.

The pursuit of precision continues to this day. Among the milestones: The first chronometer Grande Complication pocket watch in 1890. The ultra-thin pocket watches created in collaboration with Edmond Jaeger from 1903 onwards. The extreme miniaturisation of Calibre 101 in the 1920s. The award of first prize in the 1946 Chronometry competition for the Manufacture’s first tourbillon calibre. The Chronomètre Geophysic in 1958. The 1,000 Hours Control protocol in 1992. The Gyrotourbillon in 2004. The Duometre system in 2007. The Grand Prix de Chronométrie in 2009. The Master Hybris Mechanica Calibre 362 with its fully flying Tourbillon and patented S-shape hairspring in 2014. The 5^th generation of Gyrotourbillon in 2019. And the story continues….

·       A celebration of craftsmanship and an educational journey

·       A modernist gastronomy experience through a gustatory exploration

In 2024 Jaeger-LeCoultre showcases the pursuit of precision – a central tenet of the Maison since it was established in 1833 by Antoine LeCoultre. An inventor even before he taught himself watchmaking, LeCoultre was obsessed by precision and his spirit continues to drive the Manufacture’s watchmakers and engineers to this day. At Jaeger-LeCoultre, the pursuit of precision lies not only in the design and structure of calibres and the technological aids to micron-perfect component production but also in the precision of the essential human gestures behind the finishing and assembly of every component, and the decoration of every case and dial.

Today, we take accurate timekeeping for granted but, while digital devices translate atomic time (accurate to millionths of a second) to the screens of our phones and computers, mechanical watchmaking is a unique fusion of art and science. In 2024, this pursuit of mechanical precision is most eloquently expressed by the new Duometre models that take centre stage.

Deep Immersion into a Fascinating Story of Precision

At Watches and Wonders in Geneva in April, Jaeger-LeCoultre celebrates the magic of mechanical watchmaking. Revealing the intellectual rigour and technical ingenuity that lie at its very foundation, the Maison tells the intriguing story of precision in four chapters.

The Precision of Production tells the origin story of how the Maison’s founder translated his obsession with precision into inventions that were to lay the foundations for the modern watchmaking industry. It reveals how the founder’s spirit has continued to drive the Manufacture for almost two centuries, harnessing cutting-edge technologies to enhance and complement the irreplaceable value of precise hand-craftsmanship. 

The Precision of Chronometry identifies milestones in the Manufacture’s development of chronometer-certified timepieces, from pocket watches in the 19th century, to today’s new timepieces that are all certified under the rigorous 1000-Hour Control protocol. Chronometry means, simply, timekeeping accuracy, and this chapter reveals the deep research that must be undertaken to compensate for the challenges that a wristwatch faces during daily wear.

The Precision of Regulating Organs reveals the vital role of the regulating organ (namely, the balance wheel and hairspring). This is the beating heart of the watch that we find so fascinating to observe and the regularity of that heartbeat – known as isochronism – is crucial to accurate timekeeping. Visitors will discover Jaeger-LeCoultre’s ceaseless research into the ideal forms of hairsprings and innovative tourbillons, which have resulted in many patented innovations. 

The Precision of Complications explores a fundamental conundrum of watchmaking: how to maintain a perfect flow of energy while adding complications that require extra bursts of energy – by definition compromising that regular flow. This chapter demonstrates why the chronograph is the most challenging of complications in terms of precision and reveals Jaeger-LeCoultre’s ground-breaking solution. Invented by Jaeger-LeCoultre, the Duometre mechanism was introduced in 2007 in the form of a chronograph and has subsequently been united with other complications, forming a collection in its own right. 

For 2024, Jaeger-LeCoultre introduces two entirely new Duometre calibres: the Duometre Chronograph Moon (Calibre 391) and the Duometre Heliotourbillon Perpetual (Calibre 388), as well as a fresh interpretation of the Duometre Quantieme Lunaire, in steel.

A Booth Designed to Bring a Great Heritage to Life

At Watches and Wonders 2024, Jaeger-LeCoultre pays homage to the genesis of precision – a story that began many generations years before the Maison was founded and is intrinsically bound to the history of the Vallée de Joux and the metalworking crafts that flourished there before the advent of watchmaking.

To offer visitors a rich experience of this fascinating story, the design of the booth was inspired by the forges of the 18^th and 19^th centuries, where the Vallée de Joux’s blacksmiths honed their skills. The use of industrial-style design elements, and materials such as rusted metal, brushed metal, mineral stone, bricks and oak evoke a sense of time and place. At the centre of the space, the flames of the forge are translated into a spectacular Fire Pit set in a hearth of iron stone. Projected onto huge LED screens that surround the fire, a sound-and-light show narrates the story of Swiss watchmaking in the Vallée de Joux – beginning with the first inhabitants to settle this harsh and wildly beautiful landscape, tracing the arrival of the LeCoultre family, the birth of metallurgy, the dawn of watchmaking and the birth of what was to become one of the great names of fine watchmaking: Jaeger-LeCoultre. Different scenes are animated with fire effects – smoke, sparks and flames – for dramatic effect. The show is presented every hour, with a running time of three minutes.

Featuring discrete spaces and different levels, the layout of the booth invites visitors to immerse themselves more deeply in the principles of precision, exploring the many layers of the story while also discovering the Maison’s newest timepieces

A Celebration of Craftsmanship and an Educational Journey

A viewing room is dedicated to the 180 skills mastered within Jaeger-LeCoultre’s fully integrated Manufacture and the five steps essential to the creation of every timepiece: design, production, finishing, assembly and ornamentation. This space showcases the video series ‘In the Making’, which goes behind the scenes of the Manufacture to tell the story of various watchmaking skills from the perspective of the artisans themselves.

At stations located around the booth, master artisans from the Manufacture reveal the precision of gestures that are so crucial to watchmaking precision, demonstrating three of the key skills where hand-craftsmanship remains intrinsic to fine watchmaking: gear cutting, hand bevelling, and the shaping of hairsprings.

At the Atelier d’Antoine, the 2024 programme of hands-on Discovery Workshops will focus on precision, harnessing a dynamic and highly interactive format that takes participants deeper into the principles and processes of this vitally important, yet rarely highlighted, element of watchmaking. Discovery Workshop places are available by prior appointment.

A new Gastronomic Experience Inspired by Precision

For 2024, Jaeger-LeCoultre commissioned two Michelin-starred Chef Himanshu Saini to create The Precision Atelier, a new gastronomic experience dedicated to the science of ingredients. The latest collaboration under its Made of Makers programme, The Precision Atelier invites visitors to sample four savoury bites paired with beverages specially created by Chef Himanshu Saini to showcase his unique fusion of flavour and science, his remarkably precise blending of spices and the beautiful precision of his highly artistic presentations.

Watches and Wonders takes place in Geneva from 9 – 15 April 2024 and is open to the public from Saturday 13 April to Monday 15 April. Following its debut in Geneva, The Precision Maker exhibition will travel to Dubai in May 2024 and Beijing in September 2024.

Public day tickets to Watches and Wonders Geneva 2024 can be purchased online at: https://www.watchesandwonders.com/en/geneva-2024

Key facts:

• From raw metal to finished timepiece: precision at every step
• Shocks, magnetism and gravity: mastering the challenges to chronometry
• A ground-breaking solution to the incompatibility of timekeeping and complications

At Jaeger-LeCoultre it is a deeply held belief that it takes time, patience and effort to accomplish mastery in any field of human endeavour. For our Maison, precision is a core value and our quest to attain mastery in this area began two centuries ago – and will continue long into the future.

It was our founder Antoine LeCoultre’s obsession with precision that drew him to watchmaking. Even before he opened his first watchmaking atelier – while working in his father’s blacksmithing forge – he had invented machines that made it possible to cut pinions from steel with an unprecedented degree of accuracy. Taking their lead from the founder, subsequent generations of watchmakers, engineers, designers and craftsmen have worked to master precision in every area and at every stage of the watchmaking process – from conception and design to the transforming of raw materials into useable components, to the finest manual gestures involved in assembling, finishing and decoration. In 2024, Jaeger-LeCoultre tells its story of precision in four chapters.

The Precision of Production

In watchmaking, precision in the production process is the key to everything else, and this was well understood by Antoine LeCoultre, whose earliest inventions were to revolutionise the watchmaking business.

In 1830, three years before establishing his watchmaking atelier, he developed and patented a mechanical tool that cut pinion teeth from steel. Rather than being shaped by hand, one by one, multiple pinions could now be made to precisely the same pre-determined specifications, and with greater accuracy than ever before.

Fourteen years later, in 1844, Antoine LeCoultre invented the Millionometre. The first device capable of measuring a micron, it enabled not only to measure components with an unprecedented level of precision but also to miniaturise them even further. The Millionometre can be seen as Antoine LeCoultre’s inventive response to the miniaturisation made possible by the machines that he himself had invented and, in turn, the precision of its measurements made further miniaturisation possible. Very few examples of the Millionometre were made and the technology was jealously guarded by the Manufacture, where it served as the standard for precision for more than 50 years.

Continuing his pursuit of precision, Antoine LeCoultre implemented new tools to the production process such as the rounding-up tool in 1850, and the milling-cutter tool in 1860, further enhancing the ability to produce precise watch components.

Among the exceptional timepieces made possible by the ability to measure with micron-accuracy was the world’s flattest movement. Just 1.38mm thick, Calibre 145 was presented in 1907 in the pocket watch nicknamed Couteau (knife) owing to its thinness.

Ensuring that the legacy of Antoine LeCoultre’s contributions to watchmaking precision endures, swages have been preciously conserved within the Manufacture walls since 1926. Today, Jaeger-LeCoultre has more than 1,900 stamps to produce or service the Maison’s calibres.

Throughout his life, Antoine LeCoultre continued to develop new and precisely calibrated stamping and cutting machines, and mechanical lathes to turn parts. By making it possible to produce identical components in series, his pursuit of precision set the stage on which the modern watchmaking industry developed – an achievement recognised by a gold medal at the 1851 Great Exhibition in London.

As technology advanced throughout the 20^th century and continues into our current century, Jaeger-LeCoultre has embraced modern aids to precision throughout the watchmaking process. The Manufacture was an early adopter of CNC (computer numeric cutting), acquiring its first CNC machine in 1982, and of CAD as an aid to design. More recently, technologies such as spark erosion, laser cutting and 3D prototyping have turned the core stages of the production process into an exact science. However, these technologies are an adjunct to, not a replacement for, the precise human gestures involved in initial design, various stages of prototyping and the assembly, finishing and decoration of watch calibres – for it is the craft of the human hand that distinguishes high-end watchmaking from the rest, imbuing an Haute Horlogerie timepiece with its ineffable ‘soul’.

The Precision of Chronometry

Chronometry means, simply, timekeeping accuracy, and a chronometer is a mechanical calibre that exhibits a very high degree of accuracy that has been certified through a stringent testing process. Chronometer certification owes its genesis to the advancement of optic technology in the mid-19th century, which led to the establishment of observatories that enabled the precise measurement of the planetary movements that define time as we know it.

Honouring the founder’s obsession with precision, the Manufacture Jaeger-LeCoultre has developed many chronometer calibres during its 190-year history. To achieve the necessary degree of accuracy, every chronometer timepiece is the product of deep research into how to compensate for the challenges that a watch is subjected to. To produce a chronometer mechanism requires great technical know-how: pinions must be precisely shaped and gears perfectly meshed; working surfaces must be immaculately polished to reduce friction; and metals must resist temperature variations.

In the quest for precision and durability, mechanical watchmaking faces several challenges, ranging from bumps and shocks and magnetism to energy and gravity.

Challenge 1: Bumps and Shocks

Movements that beat at a higher frequency are less disrupted by shocks. Addressing the need for more resilient movements, the Maison introduced in 1970 Calibre 916 which operates at a high-frequency of 28,800 vibrations per hour (4Hz). By doing so, the Manufacture set a new standard at the time, breaking the traditional 3Hz or 2.5Hz, which was the norm back then. In the constant quest for precision, Jaeger-LeCoultre developed the Calibre 781 for the Master Compressor Extreme Lab, achieving remarkable precision and reliability. Among other innovations, the hairspring has a special protection device that limits the motion of the spring during periods of extreme situations, such as shocks.

Challenge 2: Magnetism

Magnetism can affect the accuracy of mechanical watches by magnetizing certain components, causing them to run slower or faster. Early on, the Manufacture explored various materials to enhance hairspring performance, leading to the pioneering use of a palladium hairspring in the LeCoultre Calibre 18RV for the Chronograph Pocket Watch at the end of the 19th century. This innovation earned it a chronometer certification. To counteract magnetization further, the 1958 Geophysic was engineered for durability, water resistance, and precision, incorporating a soft iron inner case for magnetic protection, making it a certified chronometer and one of the first wristwatches to offer such functions.

Challenge 3: Energy

Mechanical watches operate on a wound spring that powers the movement. A low power reserve may affect timekeeping accuracy, as the unwinding mainspring reduces the balance wheel's oscillation amplitude, leading to unstable movement and inconsistent timekeeping. Watches with longer power reserves can delay the onset of 'low energy production,' ensuring a more regular 'heartbeat' and maintaining timekeeping accuracy for extended periods. In the 19th century, the Manufacture's watchmakers tackled the challenge of added complications by launching the minute repeater Calibre 19/20RMSMI in 1881, featuring two barrels powering a single gear train for both timekeeping and complications. This innovation laid the groundwork for the 21st-century revolutionary Duometre concept. Pursuing the optimization of energy efficiency, in 2004 the Master Eight Days Perpetual emerged as a perpetual calendar with an 8-day power reserve, embodying excellence in performance and elegance in design.

Challenge 4: Gravity

Gravity influences mechanical watch accuracy by affecting the balance wheel and escapement depending on the watch’s position, resulting in timekeeping variations. To counteract this, some watches feature tourbillons that continuously rotate these components to even out gravity-induced errors. Jaeger-LeCoultre introduced the remarkable Calibre 170 in 1946 for chronometric competitions, achieving multiple awards. Always driven by the inventive spirit of Antoine LeCoultre, in 2004 the Maison pushed back the boundaries of watchmaking by introducing multi-axis tourbillons.

The Manufacture LeCoultre was already producing chronometer-certified pocket watches in the 19^th century – 100 years before modern aids to precision, such as CNC machines and laser-cutting, had even been imagined. While some of these watches had simple mechanisms – and thus fewer variables that can affect timekeeping accuracy – the Manufacture also created chronometer-certified watches with complications and, in 1890, met the ultimate challenge of producing a chronometer-certified Grande Complication pocket watch.

In 1992, Jaeger-LeCoultre introduced its 1,000-Hour Control certification. One of the watch industry’s most stringent testing protocols, it tests not only the calibre alone but also the entire cased-up watch and demands greater accuracy than the standard Swiss chronometer certification. The first movement to receive the 1,000-Hour Control certification was Calibre 899, the pillar of the Master Control collection.

Continuously seeking ways to improve chronometry, innovations in recent years have focused on materials for key components – including silicone and new lubricants to reduce friction and thus enhance energy transmission – new constructions for gears and balance wheels, and new shapes for escapement wheels and pallets, all of which have improved isochronism and thus accuracy of timekeeping.

The Precision of Regulating Organs

The regulating organ is one of the most important parts of a movement. Composed of the balance wheel and the hairspring (known as the spiral in French), it is the element that we find so mesmerising to observe in mechanical calibres, the part of the movement that appears as if living and breathing – its beating heart. Controlled by the expansion and contraction of the hairspring, the regularity of that heartbeat – known as isochronism – is crucial to accurate timekeeping.

Jaeger-LeCoultre is one of the few watchmaking Maisons with the specialised skills in-house to craft and shape hairsprings in different forms and this key component has been the subject of deep research by the Manufacture’s engineers for many decades. In the early days, considerable attention was devoted to materials and, in 1890, the Manufacture pioneered a palladium hairspring. More recently, efforts have been focused principally on the form of the hairspring and on tourbillons.

The shape and attachment (terminal curves) of a hairspring determine the way that it expands and contracts. While it is standard practice use flat hairsprings, Jaeger-LeCoultre’s engineers have studied different configurations to identify the shapes that offer the most concentric – and therefore regular – oscillation according to the particular construction of the regulating organ. They discovered, for example, that a flat (Breguet) hairspring delivered the best results in the Gyrotourbillon 5 while maintaining a very small Gyrotourbillon size, whereas in the Tourbillon Cylindrique, a cylindrical hairspring with two terminal curves beats with a concentricity impossible to achieve with a traditional hairspring. The Manufacture’s specialists have also developed spherical and semi-spherical hairsprings for different calibres – and their research continues.

Recognising that the effect of gravity also has an impact on the finely tuned balance of a watch mechanism, they also studied the regulating organ as a whole and found a solution in the tourbillon. A device that had been largely neglected since its invention at the end of the 18^th century, the tourbillon counters the effects of gravity by rotating the balance wheel within a cage. In 1946, Jaeger-LeCoultre’s first tourbillon movement – Calibre 170 – won the Neuchâtel Observatory chronometry competition, and in 1993 the Maison created its first tourbillon wristwatch.

Because the tourbillon was initially devised for pocket-watches, so does not compensate for the effects of gravity in all positions, Jaeger-LeCoultre’s watchmakers added a second axis that turns perpendicular to the first, to achieve a three-dimensional rotation. The Maison broke new ground with the launch of its first multi-axis tourbillon in 2004 – the emblematic Gyrotourbillon – followed in 2012 by the Spherotourbillon. This was followed in 2014 by the ultra-thin Calibre 362 featuring a flying tourbillon held on a peripheral ball bearing system and fitted with Jaeger-LeCoultre’s patented S-Shape hairspring. Further development of the original Gyrotourbillon led to the release of a 4^th generation in 2016 and in 2019, the Gyrotourbillon 5 housed in the Master Hybris Mechanica Calibre 184.

The Precision of Complications

The fundamental requirement for accurate timekeeping is that the power supply delivered from the movement’s barrel to the regulating organ should be absolutely steady, in order to maintain isochronism – the perfect regularity of the mechanism’s ‘heartbeat’.

Requiring a watch movement to drive an additional complication carries the risk of jeopardising its timekeeping accuracy – for the simple reason that the complication itself requires power in order to function. Moreover, while displaying the time accurately, the watch must also ensure that the complication’s indications – for instance, a moon phase, a celestial map, elapsed seconds – are displayed on the dial with the greatest possible precision.

Some complications create a slow and relatively steady drain on the power supply over time – for example, calendars of varying degrees of complexity. Other complications – including chronographs and minute repeaters – require a high burst of energy for a very short period. The chronograph poses an added challenge to precision because its entire purpose is to accurately measure and display precise, and very small, intervals of elapsed time.

Since the early days of the Manufacture, our watchmakers have not only mastered the chronograph but also have associated it with other complications, devising ways to successfully manage the transfer of energy between the timekeeping function and the operation of the complications, while minimising its effect on isochronism.

In their search for a solution to the conflicting demands of timekeeping and complications, Jaeger-LeCoultre’s engineers developed the Duometre concept. Patented by the Manufacture and introduced in 2007, a Duometre mechanism features two barrels, each with a separate and independent gear train, housed within a single calibre and linked to a single regulating organ. One gear train is responsible for powering the time indications, and the other for driving any additional functions. Because it ensures that the operation of the complication does not compromise the timekeeping function, and thus guarantees operating accuracy, this concept has opened the door to continuously expanding horological complexity.

For the first application of the Duometre concept in 2007, Jaeger-LeCoultre watchmakers set themselves the hardest challenge: to develop a chronograph watch that would be as accurate as a chronometer. The result was the Duometre à Chronographe, fitted with Calibre 380 – a fully integrated column-wheel chronograph movement. The Duometre mechanism has since been employed for other complications, including moon phases, a GMT function, a classical tourbillon and, in 2012, a spherical tourbillon.

In 2024, Jaeger-LeCoultre introduces two new Duometre movements: Calibre 388, which powers the Duometre Heliotourbillon Perpetual, features an entirely new tourbillon configuration, which rotates on three axes and creates a ‘spinning top’ effect. And Calibre 391 unites a chronograph with a moon-phase display in the Duometre Chronograph Moon.

Incorporating almost eight decades of accumulated expertise, the new Duometre calibres represent another step forward in the Maison’s continuing quest to master precision. And thus, the story begun by the founder continues…