anojoule scale: two words at the centre of the tenth Fundamental Invention from Greubel Forsey, presented for the twentieth anniversary of the brand, which was founded in 2004.

“Greubel Forsey is about fundamental research,” says CEO Michel Nydegger. “This takes time and resources and we are willing to make the necessary investments. We launched the Nano project in 2016. Eight years later, we have reached the stage where we can present the first model with this technology, which harnesses energy directly from the escapement.”

Welcome to nanomechanics

Greubel Forsey’s tenth invention, the Nano Foudroyante is described as its “most technologically disruptive” to date. It takes us into the realm of nanomechanics, beyond the miniaturisation of components to the nanometric scale, in which the mechanical movement’s energy is controlled on a nanojoule scale. This capacity to manage energy on a much smaller scale enables a significant reduction both in energy consumption and the number of components.

The brand has chosen to demonstrate these nanomechanical capabilities with foudroyante seconds; a hand that completes one revolution per second. This revolution is divided into segments determined by the frequency of the movement. In the Nano Foudroyante, each oscillation of the 3Hz balance produces two beats, for a total six beats per second. Thus the hand divides the second into six distinct segments.

By managing energy on a nanojoule scale, Greubel Forsey has radically rethought the design and construction of what is, by nature, an energy-intensive complication. Whereas a traditional foudroyante consumes 30 microjoules per jump, the Nano Foudroyante operates with just 16 nanojoules per jump: a reduction in energy consumption by a factor of 1,800.

The Nano Foudroyante operates with just 16 nanojoules per jump: a reduction in energy consumption by a factor of 1,800.

A “perpetual foudroyante”

The mechanism’s volume has been reduced by 90 per cent. But as the brand points out, “the focus is not just on measuring fractions of a second but as proof of concept for a completely new approach to watchmaking, which is why this Nano Foudroyante was chosen to be a perpetual display.”

A traditional foudroyante uses an entire gear train to divide the second. The Nano Foudroyante does away with this to instead source the information directly, distributing and managing the energy from the movement through a small number of low-inertia wheels.

Fewer parts means smaller volumes: the compact Nano Foudroyante EWT comprises 428 components; the movement does not exceed 31mm in diameter, “which translates into a 37.9mm case, our smallest ever,” Michel Nydegger adds.

Greubel Forsey is known for its research and as a master of the tourbillon; accordingly, this Nano Foudroyante is incorporated into a flying tourbillon – its first ever. With a characteristic eye for detail, even as the flying tourbillon constantly rotates, the Nano Foudroyante’s dial remains permanently aligned towards twelve o’clock for perfect readability. Along with the flyback function, these features complete Greubel Forsey’s 10th Fundamental Invention: a Nano Foudroyante, in a flying tourbillon, with an oriented reading axis.

The first use of tantalum

This inaugural edition of the Nano Foudroyante EWT will be limited to 11 pieces. Flawlessly finished, its design is deliberately sober, allowing the disruptive technology to take centre-stage. Cased in white gold, the bezel and the ring on the open caseback are in tantalum – the first time Greubel Forsey has used this metal. Admired for its grey/blue lustre, tantalum has a melting point above 3,000°C; working with it therefore requires rare expertise.

The aesthetic is recognisably that of Greubel Forsey, whether the polished relief engravings, “Nano Foudroyante” and “Greubel Forsey”, on a hand-hammered ground, the hand-executed satin finish of the white gold or the architectural movement, centred around the column wheel with rare 3D monbloc geometry and visible through the sapphire back. Marking this milestone, the inscriptions “2004 – 2024” and “20e Anniversaire” are engraved on the back.

“A completely new chapter is beginning, not just for our brand but for mechanical watchmaking in general, with an entirely different approach to energy management.”

Combining technologies

“Every time we research a new technology, we learn more. We can then combine the results of our research and apply them more widely to our watches in the future,” Michel Nydegger continues. “In this instance, a completely new chapter is beginning, not just for our brand but for mechanical watchmaking in general, with an entirely different approach to energy management. We are making progress towards our goal of 180 days of power reserve.”

How does this cutting-edge research tally with the brand’s objective to open up to a wider audience? Surely there is a contradiction between the two?

“Not at all,” Nydegger replies. “We don’t offer two standards of finishing or technology. Everything we do accumulates in terms of savoir-faire. We have, however, readapted our objectives from our previous goal of 500 pieces a year to maintain production at its current level of 250 watches a year, which is still an enormous challenge. For a brand such as our, it’s almost more complicated to make a “simple” watch, given the level of finishing that has to be applied to a larger surface. We’ll continue to focus on what we have been doing for the past 20 years, namely fundamental research and complication.”

Demand for the “entry-level” Balancier 3 remains high. Released last year and priced at CHF 160,000, it has introduced a wider audience to the brand (read our article here). The launch of the Nano Foudroyante EWT reshifts the balance towards what is Greubel Forsey’s core identity: very high-end watchmaking that associates fundamental research with pure craftsmanship. With this latest release, the brand is the architect of a major leap in technology that it hopes will be “as significant as the one that led from tower clocks to wristwatches.”