Introducing: The Bianchet UltraFino Sapphire — A Transparent Take On The Ultra-Thin Tourbillon
Sapphire-cased watches have crept up on me lately. I used to think of them as fragile showpieces, destined for safes rather than wrists, but something has shifted. It probably started with the ArtyA Luminity Wavy collection, which made me stop and think about how sapphire can do more than just look flashy. Now, with Bianchet’s latest release, that spark of curiosity grows stronger. The new UltraFino Sapphire is a fully transparent take on the brand’s ultra-thin skeleton tourbillon, and on paper, it ticks a lot of boxes for me.
I haven’t seen it in hand yet, but with Geneva Watch Days around the corner, I’ll hopefully get the chance soon. Judging by the press images, this could be one of the most compelling sapphire watches in recent memory.
A slimmer, more wearable Bianchet
The UltraFino collection already marked a turning point for Bianchet. It was the brand’s most moderately sized family to date, offering a tonneau case with proportions that feel more wearable than its earlier, chunkier pieces. At 40mm across, 47.5mm long, and just 9.8mm thick, the new UltraFino Sapphire manages to become the slimmest full-sapphire tourbillon on the market. To put that in perspective, most sapphire-cased watches from other brands fall anywhere between 11.5mm and 23mm thick.
That size reduction is not simply cosmetic. Sapphire is notoriously difficult to machine, and Bianchet has given the case a 1.2mm curve, a detail that makes the process exponentially more demanding. Getting a case under 10mm required both mastery of the material and a movement slim enough to match. It is a feat that feels like a statement of intent: sapphire can be elegant and ergonomic, not just a crystal block with a movement inside.
Legibility is a close second
If you’re not into skeletonized watches, you might want to look away now. Bianchet leans heavily into open-worked design, guided by Fibonacci spirals and the Golden Ratio. That philosophy gives the UltraFino Sapphire a striking, architectural feel. Of course, skeletonisation comes with a trade-off. Legibility isn’t as crisp as a three-hander with bold lume plots, but then again, nobody buys a sapphire skeleton tourbillon expecting tool-watch clarity. The appeal lies in watching light pass through the case and movement, seeing how the Fibonacci-shaped gold rotor dances with every wrist flick, and following the tourbillon’s rotation at six o’clock.
This is horology as theatre, and in that context, the UltraFino Sapphire plays its role beautifully.
The UltraFino Sapphire’s UT01 movement
Inside the case is Bianchet’s UT01, an automatic tourbillon caliber with a mere 3.85mm profile yet resistant to shocks of up to 5,000 g. It’s rare to see shock resistance and ultra-thin design paired in the same sentence, but Bianchet has clearly made durability a priority. The bridges are sculpted from Grade 5 titanium, brushed and polished, then hand-chamfered over the course of 15 hours. It’s meticulous work, but the result has real presence.
That Fibonacci rotor is more than just decoration. Its 18K gold weight ensures reliable winding, and its interlocking spiral design ties back to the brand’s obsession with mathematical harmony. This is where Bianchet’s architectural vision becomes clear: the watch is as much about proportion and geometry as it is about mechanics.
Everyday practicality in sapphire
Sapphire watches often live in the “look, don’t touch” category, but Bianchet has worked hard to make this piece more than a display object. The hardness and scratch resistance of sapphire are obvious benefits, but water resistance is where most of these watches falter. Typically capped at 3 ATM, they can’t handle much more than a splash. The UltraFino Sapphire, however, reaches 5 ATM thanks to a white rubber joint that doubles as a design flourish. Instead of hiding it, Bianchet has highlighted it, framing the case with a clean white line that continues into the strap.
The strap itself comes in natural vulcanized rubber, with white supplied as standard and black as an interchangeable option. Both are secured by a titanium folding clasp, keeping the watch consistent with Bianchet’s lightweight yet high-performance approach.
A trilogy of materials
What I appreciate about Bianchet is that sapphire is not an isolated gimmick. The UltraFino collection also includes versions in titanium and carbon composite, each chosen for a specific balance of strength, weight, and finish. The sapphire variant completes this “trilogy” of materials, offering crystalline transparency where the others provide matte depth or metallic sheen. Seen together, the UltraFino family feels like a study in contrasts, with sapphire naturally stealing the spotlight in my opinion.
Why the UltraFino Sapphire matters
The Bianchet UltraFino Sapphire will retail for CHF 85,500 before taxes. That is no small figure, but it’s also not entirely out of line for a full sapphire-cased tourbillon, especially one that measures under 10mm thick. Pricing aside, what excites me most is that Bianchet has made a sapphire watch that sounds wearable, at least on paper. It is slim, curved, and engineered with enough durability to handle daily use.
I’ll reserve my final judgement until I’ve had the chance to try it on next week in Geneva, but right now, my fascination with sapphire cases shows no sign of slowing down. Bianchet’s UltraFino Sapphire might just be another step in that ongoing story.
