Yema Unveils a New Dress Watch Collection with the Senans Grand Lune CMM.22

Founded in 1948 by Henry-Louis Belmont in Morteau, France, Yema made a name for itself as a producer of ultra-reliable purpose-built tool watches. Its iconic 1963 Superman watch, for example, was a heavy-duty instrument watch for professional divers, while the Flygraf chronograph was geared for pilots. Under Ambre France since 2009, Yema’s mission is to reclaim French mechanical watchmaking. Using the brand’s proprietary ultra-slim CMM.20 calibre with a micro-rotor, Yema is producing some surprising watches that reach well beyond the brand’s signature repertoire of tool watches. The latest surprise is the launch of the new and dressier Senans collection, spearheaded by the brand’s first moon phase watch in a delectably slim case.

As part of a push to return to “Made in France” watchmaking, Yema developed its proprietary Calibre Manufacture Morteau (CMM.20) with French watchmaker and movement designer Oliver Mory. The CMM.20, a 3.7mm-thick micro-rotor movement with a robust 70-hour power reserve, is the foundation of a growing collection of ultra-thin watches and made its debut in 2022 in the Wristmaster, the brand’s take on the integrated sports watch. Extending into the iconic Superman and Navygraf families, the brand released the dressier Granvelle collection with a cushion-shaped case.

The Senans Grand Lune parts company with the Granvelle with its classical round case and a stepped, mirror-polished bezel – a direct nod to vintage Calatrava-style dress watches of the 1940s and 1950s. At 38.5mm in diameter, 8.7mm thick (not including the double-domed sapphire crystal over the dial), and 46.4mm lug-to-lug, the Senans ticks the slim dress watch box category. Although its diameter is wider than vintage dress watches, it hits the sweet spot for contemporary dress watch tastes. In contrast to the mirror-polished bezel, the flanks are brushed, and the lugs curve gently to follow the wrist’s contours.

The collection takes its name from the Royal Saltworks of Arc-et-Senans, an 18th-century architectural landmark near Morteau. Renowned for its distinctive semicircular architecture, the saltworks’ geometry is echoed in the large asymmetrical aperture for the Grande Lune at 7 o’clock. In an engaging blend of old and new, the moon phase display is framed by a traditional barleycorn guilloché-like pattern (stamped), and the moon is crafted from a solid block of Super-LumiNova. The subtly domed moon, with its realistic lunar markings, glows beautifully in the dark.

But there is more to this moon phase complication than its glowing presence. Unlike conventional moon phases, the moon on the Senans is a stationary block of Super-LumiNova. To animate the lunar phases, Yema developed an ultra-thin rotating mechanical bilobe that sweeps over the luminous orb like a mechanical shadow, depicting the lunar cycles of waxing and waning.

Reflecting the moon’s luminescence, the ring framing the central guilloché decoration, the hour markers and hands are treated with Super-LumiNova. The circular-brushed chapter ring, bearing alternating long and short baton-shaped indices, is framed by a raised minutes track. The Senans Grand Lune comes in three dial colours: a dramatic black variant, a more conventional blue dial and a very appealing golden dial.

Integrating a moon phase into a thin automatic movement was challenging, particularly given the large dimensions and additional mass of the heavy 3D luminescent lunar sculpture. Engineered again with Olivier Mory, the complication adds just 1mm to the micro-rotor architecture of the CMM.20, bringing the total height to 4.7mm. Still beating at 4Hz and delivering a 70-hour power reserve, the calibre CMM.22 features contemporary charcoal grey electroplated finishes, creating a powerful contrast with the polished screw heads and purple jewel bearings.

All three colourways of the Senans Grand Lune are limited to 200 pieces and can be paired with a leather strap for EUR 2,470 or a mesh bracelet for EUR 2,570. Quite a pleasant price considering the mechanical content… More information at yema.com.