Yema's New Senans Grande Lune CMM.22 Micro-Rotor Dress Watch Collection

Yema, a French horological brand established in 1948 by Henry-Louis Belmont, has historically been recognized for its resilient, purpose-driven timepieces, such as the iconic Superman dive watch and the Flygraf chronograph for aviators. Following its acquisition by Ambre France in 2009, Yema embarked on a mission to rejuvenate French mechanical watchmaking. This endeavor has seen the brand utilize its proprietary ultra-thin CMM.20 micro-rotor caliber to create a diverse range of watches that extend beyond its traditional robust designs. The latest addition, the Senans collection, introduces a new, refined dress watch line, distinguished by Yema's inaugural moon phase complication housed within a remarkably slender case.

The Senans Grande Lune distinguishes itself from previous collections like the Granvelle through its elegantly classic circular case and a polished, stepped bezel, reminiscent of vintage Calatrava-style dress watches from the mid-20th century. With a diameter of 38.5mm, a thickness of 8.7mm (excluding the domed sapphire crystal), and a lug-to-lug measurement of 46.4mm, the Senans model perfectly encapsulates the modern preference for a sleek dress watch profile. While its diameter is somewhat larger than historical dress watches, it aligns well with contemporary tastes. The case's flanks are finished with a subtle brush, contrasting with the polished bezel, and the lugs exhibit a gentle curve for enhanced wrist comfort.

The collection draws its name from the 18th-century Royal Saltworks of Arc-et-Senans, an architectural marvel near Morteau. The distinctive semicircular design of the saltworks is subtly echoed in the watch's prominent, asymmetrical moon phase aperture positioned at 7 o'clock. This moon phase display, a captivating blend of tradition and innovation, is encircled by a stamped barleycorn guilloché-like pattern, while the moon itself is crafted from a solid block of Super-LumiNova. The gently domed moon, featuring realistic lunar surface details, radiates a beautiful glow in low-light conditions, adding a unique aesthetic dimension.

Beyond its striking luminosity, the moon phase mechanism in the Senans offers an inventive approach to displaying lunar cycles. Unlike conventional moon phase complications where the moon rotates, the Senans features a static Super-LumiNova moon. Yema engineered an ultra-thin rotating mechanical bilobe that precisely sweeps across this luminous orb, creating a "mechanical shadow" that dynamically illustrates the moon's waxing and waning phases. This innovative design not only captivates the eye but also represents a clever solution to integrating a complex function into a slim movement.

The luminous theme extends to other elements of the dial, with the ring encircling the central guilloché, the hour markers, and the hands all treated with Super-LumiNova, ensuring readability in various lighting conditions. A circular-brushed chapter ring features alternating long and short baton-style indices, framed by a raised minutes track at the periphery. The Senans Grande Lune is offered in three distinct dial variations: a striking black, a traditional blue, and an especially attractive golden hue, catering to diverse preferences.

Integrating the moon phase complication into such a thin automatic movement presented a significant engineering challenge, particularly due to the large size and substantial mass of the three-dimensional luminescent moon sculpture. Developed in collaboration with Olivier Mory, this intricate complication only added 1mm to the CMM.20 micro-rotor architecture, resulting in a total movement height of 4.7mm. The CMM.22 caliber maintains a frequency of 4Hz and boasts a robust 70-hour power reserve. Its contemporary aesthetic is further enhanced by charcoal grey electroplated finishes, which create a striking visual contrast with the polished screw heads and vibrant purple jewel bearings.

All three color variants of the Senans Grande Lune are produced in limited editions of 200 pieces each. Customers can choose between a leather strap for EUR 2,470 or a mesh bracelet for EUR 2,570. This pricing, considering the sophisticated mechanical components and refined design, represents an appealing value proposition for discerning watch enthusiasts. The introduction of the Senans Grande Lune collection underscores Yema's commitment to blending its historical legacy with modern watchmaking innovation, particularly in the realm of dress watches, reinforcing its position in the competitive landscape of French horology.