Geneva Watch Days 2025: Bianchet presents full visibility with the "UltraFino Sapphire"

With this reinterpretation, the brand presents its ultra-thin skeleton tourbillon in a fully transparent sapphire case (40 × 47.5 mm), revealing every detail of the movement's architectural skeleton. The "UltraFino Sapphire" combines this with true everyday practicality.

The hardness and scratch resistance of the sapphire are complemented by a white rubber gasket, providing a water resistance of 5 bar for the tonneau case. Combined with the ergonomic curve of the tonneau case, it's unexpectedly light and comfortable to wear, making it a real candidate for daily wear, promises Bianchet.

The white seal is not hidden but rather highlighted, forming a clear graphic line around the case, transforming a technical element into a design feature. At just 9.8 millimeters thick, the "UltraFino Sapphire" is one of the thinnest all-sapphire watches on the market.

Achieving the sleek silhouette required not only perfecting the sapphire machining process but also developing an exceptionally slim movement that fits within these demanding dimensions without compromising the watch's durability and precision.

Automatic movement with complication and Fibonacci spiral

The result is the tourbillon caliber UT01: an ultra-thin automatic movement with a thickness of just 3.85 millimeters and a shock resistance of 5000 g – a rare combination in haute horlogerie.

The bridges, made of Grade 5 titanium, are beveled by hand in over 15 hours and form the backdrop for the gold rotor, which displays the Fibonacci spiral.

This is a spiral-shaped figure created from the numbers of the Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ... Each number is the sum of the two previous ones. To create a spiral, squares are drawn next to each other, the sides of which correspond to the Fibonacci numbers (1×1, 2×2, 3×3, 5×5, 8×8, ...). A quarter circle is drawn inside each square. When these quarter circles are placed side by side, a spiral is created.

The white vulcanized natural rubber strap with a Grade 5 titanium folding clasp ensures a secure fit on the wrist. The white color echoes the distinctive sealing joint of the case, creating a harmonious visual transition from the case to the strap. A second strap made of black, vulcanized natural rubber is available upon request for a more striking contrast.

(RRP 85,000 CHF (plus VAT))