Minerva is the quiet half of Montblanc's watchmaking. The Villeret manufacture, founded in 1858 and absorbed into Montblanc in 2007, builds a small number of movements a year to a standard the group's regular collections do not attempt. Its Exo Tourbillon is the house signature, and for 2026 it appears as reference 137548, a limited run of 18 pieces in yellow gold with a deep olive-green dial.
What the Exo Tourbillon actually does
The name describes the construction. In a normal tourbillon the balance wheel sits inside the rotating cage, so the cage has to be large and heavy enough to carry it. Minerva moves the balance outside the cage and suspends it above, which lets the cage stay light while the balance itself grows. Here the screw balance measures 14.5mm across, unusually large, carries 18 regulating screws, and is timed by moving those screws rather than by a spring-loaded index. The manufacture quotes a balance staff mounted to tolerances of as little as five microns. The lower mass in the cage and the bigger, steadier balance are meant to hold rate better than a conventional layout, and the whole assembly is left open on the dial so you can watch it work.
The calibre M16.68
Behind the dial is the hand-wound Minerva calibre M16.68, made up of 218 components and 19 jewels. It beats at 18,000 vibrations per hour, a slow 2.5Hz that suits the large balance, and holds around 50 hours of power. The frequency is period-correct for a movement built in the old Minerva tradition, where the chronograph and tourbillon calibres were designed to run at leisurely rates and be finished by hand. This is a time-only watch built around the tourbillon: hours and minutes, a running tourbillon, and nothing else to distract from either.
Olive green over gold
The dial is the news. It is finished in a deep olive-green guilloche, with the hours and minutes pushed off to the upper left in a separate black onyx sub-dial marked in applied gold Roman numerals and signed Minerva, Depuis 1858 and Swiss Made. The tourbillon opening sits below it, and an XVIII cartouche on the right marks the edition. The case is 18k yellow gold, 44.8mm across and 15.03mm thick, a large watch that the height of the suspended balance requires. Water resistance is a dress-watch 30 metres.
Price and availability
Reference 137548 comes on a semi-matte olive-green alligator strap with an 18k yellow-gold triple-folding clasp. It is limited to 18 pieces, priced at EUR 160,000. It is the kind of watch Minerva makes a handful of every year and rarely advertises, aimed at the collector who already knows what the Villeret workshop is and wants the version almost nobody else will have.
Sources: Monochrome Watches and Montblanc.
