Return Of The King: The Bulgari Octo Finissimo Ultra COSC
Bulgari takes back the world’s record for the world’s thinnest mechanical watch – and it’s a certified chronometer.
Back in 2022, if you were a fan of ultra thin watchmaking, you got a one-two punch. First, Bulgari released what was at launch the world’s thinnest mechanical watch, ever – the Octo Finissimo Ultra. The Octo Finissimo Ultra was just 1.80mm thick – or I should say, is 1.80mm thick; the watch is still available as a special order. Just four months later, Richard Mille fired back with the RM UP-01. The UP-01 set a new record, albeit by a very thin margin – it was 1.75mm thick. To get there, RM did away with a conventional crown – for that matter, it did away with the crown, period; winding and setting was via a special screwdriver-like tool and a function selector, and there was no running seconds hand either. At that point it seemed as if the RM UP-01 was likely to remain the world’s thinnest watch more or less indefinitely. Not only was the Richard Mille so radical in its technical solutions, that anything else beating it seemed impossible, it also seemed as if the whole pursuit of ultra thin watchmaking had reach a natural end point.
However, it’s clear now that counting Bulgari out was a mistake. Bulgari’s new Octo Finissimo Ultra COSC has just set a new world’s record, coming in at just 1.70mm thick – 0.05mm thinner than the RM UP-01, which was itself 0.05mm thinner than the original Bulgari Octo Finissimo Ultra, which was in turn, 0.20mm thinner than the 2mm thick Piaget Altiplano Ultimate Concept watch, released in 2018.
The new Octo Finissimo Octa Ultra COSC achieves the new record, according to Bulgari, by “optimizing” the crystal, which was already just 0.3mm thick in the original Octo Finissimo Ultra. By the numbers, this means that the new crystal on the new Ultra is now 0.2mm thick, as Bulgari says that the “limits of movement slimness had already been reached with the Octo Finissimo Ultra.”
The Octo Finissimo Ultra COSC therefore follows the same basic playbook in terms of movement engineering followed by its predecessor, and indeed by record-setting ultra thin watches going back further than you might expect – all the way back, in fact, to the Audemars Piguet ref. 25643. In 1986, this watch set a world’s record for the thinnest automatic tourbillon, and thinnest tourbillon wristwatch, period. This record was held by AP right up until 2018, when Bulgari took the record with the Octo Finissimo Tourbillon Automatic, which when launched, was a triple world’s record – the world’s thinnest automatic watch, the world’s thinnest automatic tourbillon, and it’s the world’s thinnest tourbillon.
The AP 25643, as well as the Piaget Altiplano AUC, the Bulgari Octo Finissimo and Octo Finissimo COSC, and the Richard Mille RM UP-01, achieves it slimness by doing away with the normal case and movement construction of a conventional watch. Instead of a movement with a baseplate and bridges, sitting inside a case with a crystal, bezel, and caseback, all of these watches use the back of the watch as the movement mainplate (or you could say, the movement mainplate is the back of the watch, which comes to the same thing).
A conventional movement also has several layers, including the keyless works for winding and setting, and the motion works, which drive the hour and minute hands, as well as, usually, either a center or small seconds hand. The question if you want to make a watch as thin as possible, then becomes what you can either leave out, or suppress somehow to the same plane as the mainspring barrel, going train, and escapement.
You also need to use, since the case is so thin, a very rigid material; the case of the Octo Finissimo Ultra COSC is tungsten carbide.
The Octo Finissimo Ultra COSC is the only one of the three most recent record holders (the other two being the Piaget and the Richard Mille) to have a running seconds hand, and unlike the Richard Mille, it can be wound and set via two crowns – one on the right for setting the time, and one on the left for winding the large mainspring barrel. (In the original Octo Finissimo Ultra the mainspring barrel ratchet wheel had a QR code laser engraved on it; the new version has a miniature Datamatrix code on the back (a Datamatrix code is basically a very small QR code). Bulgari says, “The QR code on the ratchet has now been transformed into a miniaturized Datamatrix on the back, it provides all the data relating to the watch and invites you on a personal journey into the Bulgari universe. With images and videos, it provides a better understanding of the quest for ultimate finesse, the special skills and ingenuity that went into the creation of the Octo Finissimo Ultra COSC.”
However, should you wish to avoid winding and setting manually, the Ultra COSC also comes with a special case, which can handle both functions for you. Bulgari says, “If you don’t want to use traditional methods, you can place your watch in the dedicated case, equipped with a digital display. The desired time is then programmed, and the adjustment cycle launched at the touch of a button. In a matter of seconds, the watch is perfectly adjusted and wound with impeccable precision. It’s like having a watchmaker at home.”
It’s worth pointing out that in addition to the record for thinness, the Ultra COSC is also, as the name says, a certified chronometer. This is a very big deal, at least as big a deal as the new record. Generally speaking, ultra thin watchmaking and precision timekeeping are diametrically opposed – it is no coincidence that marine chronometers have a thickness comfortably measured in inches with a ruler, rather than in millimeters with a set of digital calipers. The Ultra Cosc is therefore the world’s thinnest hand-wound watch, the world’s thinnest mechanical watch of any kind, and the world’s thinnest chronometer. It is also the only record-setting ultra thin watch to have a crown system for winding and setting in combination with a running seconds display.
Of course, this now raises the question of who or what might come up next – it took Bulgari some time, and required considerable effort, to get the record back from Richard Mille. This is not a watch you’ll see a lot of in the metal either – it’s being introduced in a limited series of 20 pieces, at $590,000. If you want a new reigning champion at the peak of its comeback, as well as a piece of watchmaking history, and you have the budget, there’s only one choice in the world for now, and it’s made by Bulgari.
The Bulgari Octo Finissimo Ultra COSC; case, 40mm x 1.70mm, with sandblasted titanium lugs, bezel, and case middle; tungsten carbide mainplate; winding and setting wheels in satin finished steel, ratchet in sandblasted steel engraved with writing and a geometric decoration. Hour and minute regulator display counters in sandblasted brass with grey PVD coating; brass hands with rhodium plating and white indexes; satin finished steel seconds wheel. Bracelet, titanium, 1.50mm thick, with integrated folding clasp. Limited series of 20 pieces worldwide; price at launch, $590,000.