Greubel Forsey Unveils the Nano Foudroyante – Limited Edition of 22 Pieces

Greubel Forsey has taken one of its boldest concepts and transformed it into a fully realized timepiece. The Nano Foudroyante, first shown in 2024 as an Experimental Watch Technology (EWT) edition, now returns as a limited series of only 22 watches. This debut signals a new chapter in the brand’s journey and highlights its 10th Fundamental Invention.

From Radical Concept to Real Creation

The original 2024 commemorative version was a technical showcase. However, the 2025 edition has evolved into a refined creation, independent of anniversaries or prototypes.

This new Nano Foudroyante is crafted entirely in 18k white gold, unlike the earlier white gold and tantalum combination. Furthermore, its dial has been reworked. A rhodium finish with a striking blue minute track forms the base, while blued steel hands and cannon pinions add contrast. The foudroyante dial now features a clean white finish with transferred numerals, which improves legibility and mirrors the sharp lines of the tourbillon aperture.

Breakthrough in Nanomechanics

At the core of this watch is Greubel Forsey’s boldest idea yet: nanomechanics. By controlling energy at the nanojoule scale, the watch achieves an unprecedented level of efficiency. Traditional foudroyante designs require around 30 microjoules per jump. In contrast, the Nano Foudroyante runs at only 16 nanojoules per jump. This marks a staggering 1,800-fold reduction.

As a result, the complication divides each second into six precise segments. A lightweight red-treated hand rotates once per second, directly driven by the 3 Hz balance wheel. There is no gear train. Instead, a minimalist set of low-inertia wheels distributes energy through the mechanism.

Case and Craft

The case measures 38.3mm × 14.3mm and is made in 18k white gold. It features a high-domed AR-coated sapphire crystal, a sapphire caseback, and water resistance up to 30 meters. The bezel is hand-polished, and the caseband shows straight-graining. On the caseback, raised engravings of “Nano Foudroyante” and “Greubel Forsey” appear against a hand-punched background.

Movement and Finishing

Inside is a Swiss hand-wound Greubel Forsey caliber with 53 jewels, 21,600 vibrations per hour, and a 24-hour power reserve with the chronograph running. Highlights include:

• Olived-domed jewels in gold chatons

• Balance spring with Phillips terminal curve

• Geneva-style stud

• Flying tourbillon with embedded Nano Foudroyante mechanism

• Three-dimensional column wheel

• Straight-grained and black-polished chronograph mechanism

The bridges and plates are made of nickel silver with frosted and spotted finishes, polished bevelling, and nickel-palladium treatment. Every element reflects Greubel Forsey’s obsession with detail and craft.

Dial and Display

The dial is a multi-layered gold structure finished in rhodium. It features a blue minute circle, small seconds, and a chronograph minute counter with polished bevels and lacquered engravings. An aperture reveals both the tourbillon and the Nano Foudroyante mechanism.

The hands are made of polished blued steel with SuperLumiNova. Chronograph hands are also in blued steel, maintaining clarity and precision. The foudroyante, finished in light alloy with red treatment, adds a burst of energy.

Strap and Presentation

The watch comes with a blue hand-sewn textured rubber strap. It secures with an 18k white gold pin buckle, hand-engraved with the Greubel Forsey logo.

A Visionary Statement

With the Nano Foudroyante, Greubel Forsey has proven its ability to turn radical experiments into groundbreaking watches. Limited to just 22 pieces worldwide, this release represents one of the maison’s most important horological milestones. It is a timepiece that redefines energy efficiency and showcases the future of mechanical watchmaking.