The Cartier Masse Mystérieuse adapts a legendary clock design into a groundbreaking new timepiece.

Earlier this year, Cartier ( revealed a heavy lineup of new pieces during Watches and Wonders, from the revived Tank Chinoise to the trio of Santos-Dumonts. Among all the stellar releases, one watch stood out with its mesmerizing see-through design, the Masse Mystérieuse. With its illusive appearance and unique skeletonized movement, the Masse Mystérieuse places a long-standing Cartier tradition into one of its most notable technical marvels.

The Masse Mystérieuse where Cartier history meets modern technology. PHOTO BY ANTOINE PIVIDORI/COURTESY OF CARTIER
The Masse Mystérieuse where Cartier history meets modern technology.

While the transparent dial adds allure, the oscillating rotor is the watch’s most eye-catching feature. All parts of the maison’s Caliber 9801C movement are built directly into the rotor and are unaffected by gravity. This feat took Cartier eight years and three prototypes to design and develop. What’s even more impressive are the floating hands that move weightlessly above the movement without the use of gears.

Available in platinum in a limited edition of 30 pieces, the 43.5 mm case of the Masse Mystérieuse features a ruby cabochon crown and either a black or a matte dark gray alligator strap. In addition, there are two unique one-of-a-kind variations: a diamond-set platinum case on the leather strap and a fully diamond-set platinum case with a diamond-set bracelet to match.

How this puzzling watch tells the time ties into Cartier’s long history of creating clocks with mysterious workings. In 1912, Louis Cartier and Maurice Couet, an expert clockmaker, created the Model A, the first Cartier mystery clock. Drawing inspiration from magician Jean-Eugène Robert-Houdin, Couet attached the hands of the watch to two crystal discs rather than the clock’s movement and used the hour circle to conceal the discs.

The resulting Model A was an illusion itself—a clock seemingly suspended within a transparent case. With the Masse Mystérieuse, Cartier has successfully revived and advanced one of its traditional designs, reiterating its position as a highly technical watchmaking brand that artfully combines heritage with modernity.