Less is definitely more complicated when it comes to designing a new watch model, especially when said model is destined to set another watchmaking world record. After introducing the world’s thinnest tourbillon at Baselworld 2014 and the thinnest minute repeater in 2016, this year, Bulgari revealed the thinnest self-winding watch, the Octo Finissimo Automatic, with an incredibly light, 5.15-mm-thin titanium case and a new movement with micro-rotor. Fortunately, we were able to get our hands on a pre-production model.

The moment a product design requires reduction, be it for a more efficient production process, a cleaner look or, as in this case, to break an existing record, things usually start to get a lot more complicated – mainly because the development team will ultimately have to devise something that hasn’t been done before.

The sandblasted titanium case ensures this is lightweight

So even though Bulgari has made a habit in recent years of breaking horological thinness records at Baselworld, the fact that the Italian brand now has launched an automatic ultra-thin version of the Octo most likely meant that pretty much every component had to be redesigned or newly developed (for example, the balance wheel had to be reduced to a smaller diameter without impacting the amplitude).

Another challenge, since thinness usually means frailty, this might be one explanation for the titanium case Bulgari used. When it comes to mechanical, self-winding movements, the majority of brands prefer to use calibers with a central rotor, which automatically adds an additional level to the overall construction. The thinnest automatic movement with a central rotor currently in production is the 1120 used by Vacheron Constantin (without date and seconds hand), measuring an impressive 2.45 mm in height.

So, a comparatively less complicated solution would be, therefore, to either opt for a manual-wind movement or go with a peripheral rotor or an integrated micro-rotor construction instead, especially if you already have an ultra-thin manual-wind movement in your collection and want to set a new world record for an automatic movement.

And since the Piaget Altiplano 900P already took the record for the thinnest mechanical watch in 2013 with a 2.0-mm-thin hand-wound movement, Bulgari more or less had to go for a self-winding and, from a wearer’s point-of-view, more convenient, automatic version with micro-rotor, given the small winding crowns you usually find on ultra-thin watches.

Despite the automatic caliber, the case is just 5.15 mm

Micro-rotor or “planetary” movements were introduced in the 1950s and 60s by Büren, Universal Genève, and also Piaget, which had introduced the 2.3-mm-thin Caliber 12P in 1959. One of the many challenges when working with a micro-rotor is that the smaller diameter of the rotor affects the winding efficiency, which requires a more complex bi-directional winding system along with a heavier rotor.

Bulgari’s new in-house movement, Caliber BVL 138 Finissimo, uses a Pt950 platinum micro-rotor for increased winding efficiency and measures only 2.23 mm. It is, in fact, the thinnest self-winding movement in production. It is only 0.23 mm thicker than the manual-wind P900 from Piaget (which uses the case as the mainplate) and 0.22 thinner than the more conventional automatic 1120 currently used by Vacheron Constantin.

The BVL 138 beats at a frequency of 21,600 vph. The movement measures 36.6 mm in diameter and has a power reserve of around 60 hours when fully wound. It is of course decorated by hand with traditional haute horlogerie finishes, including côtes de Genève, chamfered edges on the bridges, and circular graining on the mainplate. Bulgari also claims the thinnest (anti-shock) Kif/Incabloc systems ever developed for its Finissimo range.

The platinum micro-rotor used in the BVL 138 Finissimo

In short, with the new BVL 138, Bulgari has managed to squeeze an automatic movement with similar dimensions as its manual-wind counterpart, the BVL 128, into a 40-mm-large, 5.15-mm-thin case. What also sets this model apart is that the Octo Finissimo Automatic comes with the Octo collection’s distinctive faceted case; in this instance in sandblasted titanium.

This creates an extremely contemporary look and a watch that almost cannot be felt when worn on the wrist (weighing less than 50 grams with the leather strap and around 80 grams on the titanium bracelet).

The multi-faceted Octo case was first introduced in the Bulgari range in 2012 and has quickly become an immediately recognizable, and some would say polarizing, contemporary watch design. Its characteristic double bezel combines the simplicity of a circle with the faceted structure of an octagon.

The Octo Finissimo Automatic’s case is made of sandblasted, and therefore, slightly grainy, titanium and measures 40 mm in diameter. The titanium crown is topped with a black ceramic insert. Even the dial is made of titanium and features black, non-luminous hour markers and skeletonized hands; a small seconds subdial can be found at the 7 o’clock position. The case is water resistant to 30 meters despite its ultra-thin profile, making it suitable for warmer temperatures and increased humidity.

You could get your signature or initials engraved on the case

Even though we expected the (of course, small) crown to be difficult to operate, the sharp-edged design made it surprisingly easy to pull out and set the hands. The Octo Finissimo Automatic is definitely not the conservative, classic design you would expect when talking about ultra-thin watches.

Nevertheless, the Octo Finissimo Automatic, especially when worn on the matte black leather strap, manages to be elegant in a very contemporary way, despite its almost high-tech look. On the bracelet, it easily works with a more casual outfit, which probably makes it one of the most modern looking and versatile ultra-thin watches available.

In other words, the Octo Finissimo Automatic breaks with tradition, and if you think that an elegant, thin watch in this price category needs to be manual-wind, made of precious metal, and, most of all, comes with a traditional design, the Octo Finissimo Automatic is definitely not the right watch for you (the same goes for the thinnest minute repeater in 2016 with titanium case).

If, however, you agree with us that a newly launched watch model can also come with a contemporary, modern design and materials, the Octo Finissimo Auto is an incredible watch that can almost not be felt when worn, but undoubtedly has a lot of visual wrist presence.

Given the renowned design, feel and construction of Bulgari’s bracelets, we recommend choosing the titanium bracelet option first, and then selecting the matte strap for an accentuated, slightly more elegant look.