Power to the Purple: Armin Strom’s Gravity Equal Force Ultimate Sapphire Purple

The Gravity Equal Force Ultimate Sapphire, released by Armin Strom in 2021, was an evolution of the world’s first automatic watch with constant force transmission, the original Gravity Equal Force from 2019.

Now, the Gravity Equal Force Ultimate Sapphire Purple takes on a colorful new personality with a pomp-and-power purple PVD main plate that is guilloché-engraved with a grain d’orge pattern (hence the tongue-in-cheek nickname “Purple Grain”) done by the independent Finnish watchmaker Kari Voutilainen.

So, let’s take a closer look at this new special edition.

Long a symbol of royalty and wealth, purple – in all its various hues – has become something of a power statement in luxury watches over the past year. With safer choices like blue and green so prominent in the market, purple surely sets the wearer apart from the crowd.
 

Moreover, the Purple Grain’s vibrant main plate highlights the brand’s signature trio of exposed bridges (this time coated in dark gray ruthenium), which echo the pocketwatch that inspired the calibre ASB19.
 

This ground-breaking movement incorporates a stop-work declutch mechanism inside the barrel to eliminate the loss of force delivered to the balance as the mainspring in the barrel unwinds to the end of its power reserve, thus impacting timekeeping performance. The stop-work mechanism overcomes this challenge by limiting the mainspring from fully unwinding for consistent power delivery and optimal precision as the energy runs down.
 

The 72-hour power reserve is generated by a micro-rotor incorporating a unique click system with two springs built onto the rotor.

In keeping with Armin Strom tradition, the movement is finished to exacting haute horlogerie standards with anglage (polished bevels), black polishing, polished sinks, perlage, straight and circular graining, and Geneva stripes.

Additionally, the chatons, placed inside polished sinks, are finished with cerclage.
 

An experienced watchmaker spends an entire day hand-decorating just the three bridges, a defining characteristic of the Gravity Equal Force’s contemporary aesthetic. First, a matte finish is applied to the backs of the bridges, followed by straight-graining on the sides, imparted by repeatedly moving the components over abrasive paper to etch long, fine lines into the surfaces.

Then, the inner and outer edges are beveled with increasingly fine-grained files before finishing with a flash polish using gentian wood to remove even barely visible lines. Finally, a straight-grained finish is applied to the tops of the bridges.
 

Once the finishing of the bridges is completed, mirror-polished screws fix them to the movement plate. It is this movement plate that is hand-guillochéd by Kari Voutilainen’s atelier, making it the only element not decorated by the brand.

The Gravity Equal Force’s small off-center time display and dial-side micro rotor allow for unimpeded views of the movement’s mechanics and its three-dimensional modern architecture through sapphire crystals on the front and back.

When the Swiss watchmaker Armin Strom, known as a master of skeletonized watches, retired in 2006 after nearly four decades in the industry, he turned his company over to two familiar faces: Serge Michel, a businessman, and Claude Greisler, a master watchmaker. The two childhood friends had visited Strom’s workshop countless times growing up.

Their shared dream was to co-found a firm that would produce high-quality, technically innovative watches that kept with the Swiss-German horological tradition while preserving Armin Strom’s low-volume, artisanal approach to producing exposed dial-side movements with meticulous hand-finishing.
 

Thus, in 2009, the revitalized Armin Strom opened its first fully integrated manufacture in Biel, Switzerland. This breakthrough accomplishment allowed the pair to realize their complicated, contemporary horological visions free from the compromises and constraints that come with relying on outside suppliers.

Only a year later, Armin Strom presented its first watch with an in-house designed and manufactured in-house movement. In 2016, they launched the Mirrored Force Resonance, a game-changing resonating dual regulator developed to achieve maximum chronometric precision while showcasing the captivating oscillating mechanism on the dial side of the watch.
 

A few years after that, the brand’s Gravity Equal Force brought constant force mechanics to an automatic watch, an advancement that surely would have put a smile on the face of the namesake firm’s founder.

Limited to only 25 pieces per year, the 41mm Gravity Equal Force Ultimate Sapphire Purple comes on a contrasting gray nubuck strap accented with contrast purple stitching and keepers and will retail for $28,900. 
 

For more information, check out the Armin Strom website.

(Photography by Pierre Vogel)