The new Arnold & Son Ultrathin Tourbillon Koi is a beautiful reminder that this Swiss watchmaker with English roots can create stunning artistic dials on demand. This bespoke watchmaking service supplements Arnold & Son’s ongoing offerings, which include iW favorites like the Perpetual Moon, the Globetrotter and Nebula collections, all of which offer technically edgy watchmaking with distinctive designs.

Arnold & Son says customers can work with its watchmakers and artisans to make a bespoke watchcase, within which the customer can then request any movement or dial using engraving, gem setting, miniature painting or sculpted elements.

This latest one-off, the Ultrathin Tourbillon Koi, highlights Arnold & Son’s already interesting Ultrathin Tourbillon. The watch is particularly suited for personalized activity in part because of its off-center dial at 12 o’clock, which provides an empty canvas of sorts for Arnold & Son’s artisans.

The Koi

In this example, Arnold & Son artists started with a mother-of-pearl dial and created a hand-painted carp, adding sculpted lotuses around the thin flying tourbillon. Two carp can be seen swimming between lotus blossoms. One type, the Tancho carp (with its red mark on its head) swims on the right while the other swims along the left side.

Arnold & son explains that the three lotus blossoms feature petals cut from silver that has been shaped, engraved, polished and painted in white lacquer. The artist makes the each flower’s pistil in the same manner.

Then the artisan paints the carp and lotus leaves by hand, using thin brushes, depicting scales and striped fins.

Ultra-thin

Technically, the Arnold & Son Caliber A&S8200 is exceedingly thin (a mere 2.97 mm), creating a workspace not too much thicker than a traditional canvas. The caliber’s flying tourbillon (with only a lower carriage bridge) allows unfettered views of the mechanism. Additionally, the balance bridge is domed and extends slightly from the dial, which makes the tourbillon’s rotation even more interesting to watch.

Finally, note the skeletonized tourbillon main plate. With this nearly transparent component, Arnold & Son retains the piece’s overall fine attributes, or its lightness.

But don’t let that thin, airy appearance fool you to think that the caliber itself is also a lightweight. If the flying tourbillon doesn’t convince you of the high technical level at which Arnold & Son operates here, consider that this ultra-thin manual-wind movement boasts an extremely impressive ninety-hour power reserve.

None of this high-end artistic and technical work comes at a bargain however, but given the bespoke nature of the final product, its $96,700 price tag is comparable to other high-end Swiss works ­– and many of those are far from unique.

Specifications: Arnold & Son Ultrathin Tourbillon Koi (Unique piece Ref. 1UTAR.M99A.)

Movement: Caliber A&S8200, one-minute flying tourbillon, manual winding, 2.97mm thick, 90-hour power reserve, frequency of 3 Hz (21,600 vph). Finishes are as follows:

Mainplate: Côtes de Genève stripes radiating from the center and hand-engraved tourbillon bridge,

Bridges: polished and chamfered by hand,

Wheels: circular satin-finished,

Screws: blued and chamfered, mirror-polished heads,

Tourbillon carriage: satin-finished, polished and chamfered.

Dial: Miniature painting on black mother-of-pearl, silver lotus flowers, engraved and painted by hand.

Case: 42mm x 12.23 5N gold, domed sapphire crystal, water resistant to 100 feet.

Strap: Hand-stitched alligator leather with gold pin buckle.

Price: $96,700