A Breakthrough That Reshapes the Future of Mechanical Timekeeping

In the rarefied world of ultra-haute horlogerie—where invention matters as much as aesthetics—few names command the reverence of Greubel Forsey. In 2025, the independent manufacturer once again proved why it stands as one of the most intellectually rigorous watchmakers of the modern era. The Greubel Forsey Nano Foudroyante, awarded the GPHG 2025 Mechanical Exception Prize, is not merely a timepiece; it is a scientific thesis rendered wearable, a landmark achievement that pushes mechanical energy to the nanojoule frontier.

Limited to just 22 pieces, crafted in white gold, and positioned as the first fully realized production edition of its groundbreaking concept, the Nano Foudroyante marks the tenth chapter in Greubel Forsey’s ongoing pursuit of fundamental horological inventions.

A Concept Graduated: From Experimental Watch Technology to Full Collection Status

First introduced as an EWT prototype in 2024, the Nano Foudroyante was, at the time, the most radical mechanical experiment Greubel Forsey had ever conducted. The 2025 edition seen today has matured into a fully independent creation—no longer tied to commemorative or prototype status.

This evolution is visible immediately:

• The original white gold × tantalum architecture has been replaced by full white gold.
• The dial now adopts a rhodium-finished gold surface with a blue minute track, enhancing clarity and tonal sophistication.
• The hands are executed in blued steel with matching cannon pinions.
• The Nano Foudroyante display is rendered in white with transferred numerals, delivering superior legibility as it captures six discrete moments within each passing second.
• A blue textured rubber strap completes the profile—an unexpected but distinctly contemporary expression that marks a new era of Greubel Forsey design.

For the first time, the watch leaves its EWT framework and enters the Greubel Forsey Collection as a fully sanctioned masterpiece, carrying a retail price of 502,200 CHF (incl. VAT).Nanomechanics: A Revolution Measured in 16 Nanojoules

At the heart of the Nano Foudroyante lies one of the most disruptive ideas ever implemented in a mechanical wristwatch: nanomechanics, or the control of energy at the nanojoule scale.

Traditionally, a foudroyante hand—which displays fractions of a second—consumes substantial energy, often around 30 microjoules per jump in classical constructions. Greubel Forsey’s nano-engineered architecture reduces this requirement to just 16 nanojoules, an unprecedented reduction by a factor of 1,800.

How It Works

• The second is divided into six segments, aligned with the 3 Hz (21,600 vph) balance.
• A lightweight, red-finished hand performs a full revolution every second.
• There is no traditional gear train powering the display.
• Instead, a minimalistic series of low-inertia wheels, oriented directly to the balance oscillations, distributes energy with near-zero loss.
• The Nano Foudroyante dial remains at 12 o’clock at all times—even as the flying tourbillon rotates—ensuring perfect orientation and readability.

The result is an energy-efficient, continuous foudroyante unlike anything the industry has seen.

Architecture of Precision: Compact, Dense, and Highly Refined

Greubel Forsey is renowned for its sculptural, three-dimensional movements, but the Nano Foudroyante introduces new levels of spatial efficiency.

Movement Specifications (Verified)

• Manual-winding mechanical
• Power reserve: 40 hours
• Frequency: 21,600 vph (3 Hz)
• 428 components, including 142 for the tourbillon cage
• Movement diameter: 31.60 mm
• Complications:
  • Hours, Minutes, Seconds
  • Flying Tourbillon
  • Flyback Chronograph
  • Nano Foudroyante (1/6th of a second)

Despite its structural complexity, the movement sits within Greubel Forsey’s most compact case to date, measuring:

• Diameter: 37.90 mm
• Thickness: 14.34 mm
• Water Resistance: 30 m

Both the front and exhibition back employ high-domed sapphire crystals, allowing unobstructed visibility of the architectural depth that has defined the maison since its inception.

The case features straight-grained finishing, polished borders, and hand-hammered background textures engraved with “Nano Foudroyante” and “Greubel Forsey”, ensuring the exterior carries the same artisanal refinement as the movement.

The Flying Tourbillon: A Technical and Visual Anchor

Greubel Forsey’s first flying tourbillon within the Nano Foudroyante is not merely a rotational spectacle but a stability and legibility mechanism. Its integration allows the foudroyante dial to remain permanently oriented at 12 o’clock, an engineering challenge few manufactures have ever attempted.

The tourbillon completes a full rotation every 60 seconds, and its visual aperture—enlarged compared to earlier prototypes—creates a dramatic, constantly animated open-heart display.

Design Language: Sculptural, Analytical, Purposeful

Each aesthetic choice is aligned with functional clarity:

• Rhodium dial for high contrast
• Blue minute track echoing the physics-driven precision of the design
• White foudroyante sub-dial for instantaneous legibility
• Blued steel hands providing crisp visibility under the domed glass
• Textured blue rubber strap providing wearability to an otherwise academically complex instrument

The watch balances high technicality with pared-back restraint, positioning it as both a collector’s laboratory piece and an everyday wearable sculpture.

A New Chapter for Greubel Forsey’s 10th Fundamental Invention

With only 22 examples offered globally, the Nano Foudroyante is not simply another limited edition. It solidifies Greubel Forsey’s long-term research into energy distribution, legitimizing nanomechanical engineering as a future cornerstone of mechanical watchmaking.

It is, by every measure, the maison’s:

• Most energy-efficient mechanical creation
• Most compact case and movement architecture
• Most advanced chronograph–tourbillon hybrid
• Most radical reinterpretation of the foudroyante complication

Winning the GPHG 2025 Mechanical Exception Award only confirms what collectors already know: the Nano Foudroyante is one of the most significant horological achievements of the decade.