Naissance d’une Montre 4 – Le Carrousel

Naissance d’une Montre 4 – Le Carrousel marks a decisive moment in the history of the project carried by the Time Æon Foundation and supported by Greubel Forsey: the announcement of Bonniksen, a new independent watchmaking house founded in 2026 in La Chaux-de-Fonds by Maximin Chapuis and Jason Chevrolat. Heir to the golden age of English horology, this first project sets out to realise, for the first time, a Carrousel crafted by hand in a wristwatch under 40 mm – a mechanism long fallen into obscurity, now revived after years of deep historical and technical research.

The Naissance d’une Montre 4 project

In pursuit of horological transmission

The Naissance d’une Montre 4 project is remarkable from the outset. Carried by the exacting standards of the Time Æon Foundation and supported by Greubel Forsey, it embodies the ultimate expression of fine making and contributes to the perpetuation of its noblest traditions. Its singularity? To announce the launch of a new independent watchmaking house – Bonniksen – a name recognised by the discerning collector for its contribution to the pursuit of horological precision at the turn of the 20th century. With its first project, Naissance d’une Montre 4 – Le Carrousel, Bonniksen sets out to establish itself as a key figure in 21st-century watchmaking crafted by hand, uniting a tradition of artisanal excellence with a scientific horology that transcends borders.

Founded in 2006, the Time Æon Foundation has devoted nearly two decades to a single and urgent mission: to index, preserve and transmit the rarest hand-made watchmaking skills before they are lost. Its Naissance d’une Montre programme has become the most demanding expression of that mission. The first project – a hand-made tourbillon led by Michel Boulanger under the guidance of Robert Greubel, Stephen Forsey and Philippe Dufour – was unveiled in 2012 and demonstrated that 19th-century craft standards could be achieved in the 21st century. Naissance d’une Montre 2 followed, entrusted to Dominique Buser and Cyrano Devanthey with the support of Greubel Forsey and Urwerk, and sold as a pièce unique at Phillips in 2023. Naissance d’une Montre 3, led by Chronométrie Ferdinand Berthoud, applied the same exacting principles to a chain and fusée wristwatch of extraordinary complexity, completed in 2025.

Here, the transmission of rare craft knowledge finds its fullest meaning. A pupil of Michel Boulanger – professor at the Paris school of watchmaking and a central figure in Naissance d’une Montre 1 – Maximin Chapuis learned to combine technical mastery with a passion for horological history. It is through a defining encounter with Jason Chevrolat, entrepreneur, collector and consultant to the watchmaking industry, that the Bonniksen adventure begins.

Naissance d’une Montre 4 – Le Carrousel is fully aligned with the mission of the Time Æon Foundation, dedicated to the preservation and transmission of rare hand-made expertise. The support and confidence granted by Greubel Forsey attest to the level of rigour sought, while fully respecting the creative and operational independence of Bonniksen.

Bonniksen, the revival of a major name in horological history

Led by Jason Chevrolat and Maximin Chapuis, the Bonniksen house is established in 2026, with its workshop in La Chaux-de-Fonds. It rests upon a simple and radical principle: to conceive, shape and assemble every component in accordance with watchmaking in its most demanding form.

At the heart of their approach lies a revolving regulating device long overlooked and yet fundamental to the history of precision timekeeping: the Carrousel, reinterpreted after more than 5,500 hours of historical and technical research, with the support of the descendants of Bahne Bonniksen.

This exploration is rooted in the golden age of English high horology (1870–1920) and draws inspiration from such eminent houses as Bonniksen, Dent, Charles Frodsham, Nicole Nielsen and Smith & Son. The two founders thus place themselves within a cross-border tradition of craft knowledge, linking British mechanical rigour to the Swiss expertise of the Vallée de Joux in complicated mechanisms.

The Carrousel, a manifesto of independence

The Naissance d’une Montre 4 project pays homage to the Carrousel, invented by Bahne Bonniksen, a Danish watchmaker established in Coventry, England. This mechanism left its mark on the British watchmaking industry of his era and remains a symbol of ingenuity and technical rigour.

A distinguished chronometer maker and teacher of mechanics and adjustment, Bonniksen devoted the better part of his career to the development and refinement of this mechanism. In 1892, he patented and commercialised his celebrated ‘position equalising karrusel’, which he retained exclusively until the decline of the British watchmaking industry at the turn of the 20th century. The Carrousel enjoyed remarkable success at observatory trials for more than two decades, adopted by the foremost English, Swiss and German watchmakers, who made of it a mechanism of rare distinction. The conversion of the mechanical industries to the service of the nation during the Great War brought about its gradual disappearance, carrying with it the refinements Bonniksen had envisioned.

The Carrousel was invented to meet a fundamental challenge in chronometry: to ensure consistent timekeeping in all vertical positions. Its dynamic system features a rotating cage carrying the escapement and balance-spring assembly, compensating for positional errors caused by gravity. A train derived from traditional going train drives the cage independently, without any wheel fixed to the main plate, offering a robust alternative to the traditional tourbillon.

True to the idea inaugurated by Abraham-Louis Breguet, the Carrousel averages positional errors and extends the history of high horology. Its uniqueness lies in its innovative design: unlike the tourbillon, where the seconds wheel remains fixed to the plate, the Carrousel is a carried-wheel device, fitted with a mobile seconds wheel. This configuration requires that the relative speeds of the wheels carried within the cage with respect to one another be accounted for in the equations governing the rotation – represented by the ‘±’ of the house’s emblem.

Beyond the precision it affords, this mechanism is distinguished by its exceptional robustness: no fixed wheel, no risk of set-up or butting, every component pivoting with absolute accuracy. This subtle technical balance confers upon the Carrousel its exceptional singularity and bears witness to the horological excellence that the house of Bonniksen is committed to perpetuating and bringing back to life today.

The timepiece

The independent house of Bonniksen is setting out to offer a contemporary interpretation of the great works of the British chronometer makers – historically reserved for pocket watches – expressing this cross-border horology at its summit. Naissance d’une Montre 4 – Le Carrousel will introduce the first-ever Carrousel crafted by hand in a wristwatch under 40 mm. Two domed crystals will offer exceptional depth, revealing the movement from every angle.

The three-hand inverted calibre will be distinguished by its atypical three-quarter plate. The hours and minutes, off-centred at twelve o’clock on a chapter ring, will be indicated by modernised English pear-shaped hands, while a large central seconds hand will pay homage to the great scientific pocket watches. The peripheral seconds track will underline the symmetry of the movement, and a subtle eccentric aperture will reveal the mechanical splendor of the fully pivoted Carrousel, completing one full rotation in 30 seconds.

Every technical detail reflects the highest mechanical standards: screwed chatons, a mainspring barrel boss, six-spoke wheels, a maker’s mark, black polish… The noble English codes will be upheld and enriched by contemporary materials and finishes, faithful to the spirit of haute horlogerie. The rotation of the large seconds hand in 60 seconds, that of the Carrousel in 30 seconds, and the clockwise and counter-clockwise motion of the respective trains will create a perpetual interplay, as captivating to the eye as it is effective for the precision of the movement.

Naissance d’une Montre 4 – Le Carrousel will be the first timepiece crafted by hand to incorporate a Carrousel, opening the way to the Bonniksen collection and to the exploration of overlooked chapters of horological history. Supported by the Time Æon Foundation, the project embodies Bonniksen’s vision of 21st-century watchmaking crafted by hand, where technical mastery and artisanal know-how converge to deliver both excellence and performance.

David Bernard 

Director, Time Æon Foundation

Born in Brussels to a family of watchmakers, David Bernard moved to La Chaux-de-Fonds in 1988 to pursue his watchmaking studies. In 1992, he joined the world of Fine Watchmaking in the Vallée de Joux. Passionate about watchmaking and complications in particular, for over a decade he rubbed shoulders with Master Watchmakers and studied traditional watchmaking. He joined Greubel Forsey – CompliTime in 2008 and Time Æon Foundation in 2015.

Boilerplate Bonniksen

Founded in 2026, Bonniksen is an independent watchmaking house expressing an advanced expression of 21st-century fine making, where artisanal tradition and scientific horology transcend borders. Inspired by the golden age of English watchmaking in the late 19th century, it places at the heart of its approach the Carrousel – the mechanism invented by Bahne Bonniksen, a symbol of ingenuity and of technical and mechanical rigor. Born of the meeting between Maximin Chapuis, a prototype watchmaker and researcher with a profound passion for horological knowledge, and Jason Chevrolat, a visionary entrepreneur committed to the international independent watchmaking ecosystem, the house perpetuates rare knowledge and forgotten techniques, ensuring the transmission of artisanal practices and historical mechanisms. Each component is conceived, crafted and finished by hand in their high horology and micromechanical workshop in La Chaux-de-Fonds. A true 21st-century laboratory of watches crafted by hand, Bonniksen combines technical rigor and creative expression to bring forth timepieces at the pinnacle of contemporary artisanal watchmaking.

Maximin Chapuis

Co-founder of Bonniksen, prototype watchmaker of the 21st century

Maximin Chapuis was born and grew up in Provence. At just 30 years of age, his career already combines high-level watchmaking practice, historical research and the transmission of knowledge. With an early passion for applied sciences, history and mechanics, he was profoundly influenced by the launch of the Naissance d’une Montre 1 project, which confirmed his vocation.

The path quickly unfolds: micromechanics, computer-aided design, watchmaking training in the Vallée de Joux, restoration and prototyping shape a journey as intensive as it is unique. His work is notably supported by the Audemars Piguet Heritage, where he develops a rigorous approach to restoring and understanding historical mechanisms.

A pupil of Michel Boulanger at the Paris school of watchmaking, he trained by day and pursued his research by night in his own workshop. Earlier, during his studies in the Vallée de Joux, he was already questioning the limited information available on the Carrousel within the field of revolving regulating mechanisms, thereby initiating in-depth research. His work led him to the English watchmaking of the late Victorian era – the golden age of the pocket watch and a period of intense technical innovation. He developed a deep respect for such figures as Bahne Bonniksen, Dent, Charles Frodsham, Nicole Nielsen and Smith & Son.

Through restoration work, documented research and exchanges with renowned watchmakers, he reacquainted himself with the making and advanced finishing of English watches and complex Swiss mechanisms, and contributed to passing on this knowledge. He has taught precision mechanics, watchmaking and horological history at WOSTEP.

Recognised by the international watchmaking community, he became a member in 2020 of the British Watch and Clock Makers’ Guild, founded by Bahne Bonniksen in 1907, and in 2023 a Freeman of The Worshipful Company of Clockmakers of London, the oldest horological institution in the world. He is also a member of the scientific committee of Horopedia.

Today, his research and his mastery of contemporary fine making lead him to join forces with Jason Chevrolat to write a new chapter in 21st-century horology with Bonniksen.

Jason Chevrolat

Co-founder and CEO of Bonniksen, entrepreneur and expert in watchmaking

Born between the Champagne and the grands crus of Burgundy, Jason Chevrolat combines a passion for fine watchmaking with an entrepreneurial spirit. Refined, discreet and genuine, he is drawn to timepieces of pure design and expressive mechanics.

From an early age, he cultivated a relentless drive for excellence, combining the discipline of a former high-level athlete with strong technical and managerial skills. He pursued a dual course of study, simultaneously completing a master’s in entrepreneurship at ESC Troyes and a master’s in engineering at the École Polytechnique de Paris (EPF), earning both degrees in the same year, complemented by a year at the Moscow Academy of Finance.

He began his career at prestigious maisons such as Jean Dunand, Christophe Claret, and Bovet, where he honed his exacting expertise in haute horlogerie. He then turned to entrepreneurship, founding Artcuracy, a company dedicated to watch consultancy, education and the management of private collections, with a particular sensitivity for independent brands and vintage pieces.

He embraces watchmaking in its entirety, convinced that conception, development, finishing and assembly must all be held to an absolute standard of quality. He has contributed to the opening of some of the most prestigious retail spaces dedicated to independent watchmaking in Kuwait and Saudi Arabia, while sharing his expertise with passionate collectors and building bridges with emerging watchmakers, independent brands, and established maisons. Driven by a desire to bring contemporary craftsmanship to life, he focuses on revealing overlooked historical know-how to open new horizons in watchmaking.

Today, at just 36 years of age, his sharp vision and unique experience in high horology lead him to join forces with Maximin Chapuis to write a new chapter in 21st-century horology with Bonniksen. As co-founder and CEO, he acts as a catalyst in the venture, bringing vision, strategy and passion to every step of the project, while ensuring the perpetuation of the art of the hand-made Carrousel.