Yema Senans Grande Lune: Manufacture Micro-Rotor Moonphase

At $2,790, Yema's first-ever moonphase watch introduces not just a new complication for the brand, but an entire collection. The Senans Grande Lune CMM.22 arrives in three dial variations, each a limited edition of 200 pieces. It pairs a classical dress watch form with a dramatically oversized lunar display.

This release marks a significant step for the French watchmaker, establishing the new Senans line as a platform for more formal designs. Powered by a new manufacture micro-rotor caliber, the CMM.22, the Grande Lune is a clear signal of Yema's broadening ambitions. It moves beyond the tool and dive watches the brand is known for.

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An Architectural Approach to the Dial

Most moonphase complications are tucked into a small aperture, acting as a secondary feature. The Senans Grande Lune inverts this convention. The complication is the dial's main event.

Positioned asymmetrically at 7 o’clock, the oversized lunar display immediately defines the watch's character. The generous curve of the aperture is an architectural nod. It echoes the semicircular layout of the Royal Saltworks of Arc-et-Senans, the French landmark that inspired the collection's name.

The moon itself is not a flat disc. Yema uses Globolight technology to create a three-dimensional, sculpted moon from a solid block of Grade X Super-LumiNova. It features finely detailed markings that reproduce the craters and textures of the lunar surface.

Fibonacci-Inspired Guilloché

The dial's texture adds another layer of complexity. The central portion features an intricate barleycorn guilloché pattern. Yema states its design is inspired by the Fibonacci sequence and the spiral geometries found in nature.

This textured center is framed by a circular-brushed outer ring. A concentric ring of Super-LumiNova separates the two finishes, creating a luminous halo that complements the glowing moon in low light. The hands and applied hour markers also receive a Super-LumiNova treatment for legibility.

Inside Yema's CMM.22 Micro-Rotor Caliber

The engine behind the Grande Lune is Yema's Calibre Manufacture Morteau 22 (CMM.22). This is an automatic micro-rotor movement that allows for the watch's slim 8.70 mm profile. A sapphire exhibition caseback provides a clear view of the caliber and its tungsten micro-rotor.

The CMM.22 is built on the architecture of the CMM.20, the movement we first covered in the Yema x Silberstein Marine 2 CMM.20. Adding the large moonphase complication was an engineering challenge. The module itself measures just 0.83 mm thick, adding less than a millimeter to the base movement's height.

This new caliber delivers a 60-hour power reserve and is regulated to an accuracy of -3/+7 seconds per day. The moonphase is a quick-set complication, adjustable via the crown. The development demonstrates a clear progression in Yema's in-house capabilities, moving from robust divers to more complex, refined dress pieces.

Franco-Swiss Manufacturing

Yema emphasizes its regional production roots in the Jura mountains. The manufacture calibers are designed and produced in its Morteau workshops. The habillage components—cases, dials, hands, and straps—are sourced from partners in France and Switzerland, all within a 70 km radius.

This approach places the brand within the Franco-Swiss watchmaking community whose traditions were recognized by UNESCO in 2020. It's a context that sets Yema apart from many brands that rely on more distributed global supply chains.

Classical Proportions, Modern Execution

Despite the dramatic dial, the 316L stainless steel case is restrained and classical. It measures 38.50 mm in diameter with a 46.00 mm lug-to-lug distance. These dimensions, combined with the 8.70 mm thickness, create a profile suitable for a wide range of wrists and formal wear.

The case features a traditional stepped construction, with the bezel rising in layers above the case middle. This design element adds visual depth and definition. Surfaces alternate between a mirror polish on the bezel and top surfaces, and vertical brushing on the case sides.

A double-domed sapphire crystal with an anti-reflective coating protects the dial. Its curvature provides a clear view of the dial textures and the three-dimensional moon while recalling the acrylic crystals of vintage watches.

The Yema Senans Grande Lune Ref. 77.26.22.05.SNL.L9

The reference 77.26.22.05.SNL.L9 introduces the Grande Lune with a striking dark blue dial. This colorway emphasizes the astronomical theme of the collection, evoking a deep night sky that serves as a natural backdrop for the oversized 3D moonphase display.

The intricate barleycorn guilloché pattern catches the light beautifully in this blue execution, highlighting the Fibonacci-inspired spirals. The contrast between the rich blue dial and the polished steel hands, hour markers, and silver-toned case provides a highly refined, contemporary dress watch aesthetic.

As with the rest of the collection, production is strictly limited to 200 pieces. It utilizes the same 38.50mm case and CMM.22 micro-rotor movement, priced at $2,790 on the leather strap.

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The Yema Senans Grande Lune Ref. 77.26.22.06.SNL.L8

The reference 77.26.22.06.SNL.L8 presents the Grande Lune with a black dial. This execution gives the watch a more formal and traditional character during the day. The contrast between the dark barleycorn guilloché and the polished steel hands and markers is pronounced.

At night, this version offers a high-contrast light show. The luminous moon and concentric rings appear to float against the black background. This two-sided personality—classic dress watch by day, astronomical display by night—is a core part of the collection's design.

Like the other models in the collection, this reference is limited to 200 pieces. It shares the same 38.50mm case, CMM.22 movement, and $2,790 price point. It comes fitted with a leather strap.

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The Yema Senans Grande Lune Ref. 77.26.22.08.SNL.L6

The reference 77.26.22.08.SNL.L6 offers a distinctively different feel with its beige dial. This colorway leans into a warmer, more vintage-inspired aesthetic. The guilloché pattern and circular-brushed track take on a softer appearance.

This variant provides a lower-contrast look compared to its blue and black counterparts. The interplay of light across the textured surfaces becomes a more subtle effect. Fellow dialheads will appreciate how the light catches the intersecting spirals of the central pattern.

It is housed in the same 38.50 mm x 8.70 mm steel case and powered by the CMM.22 caliber. The production is also capped at 200 units for this specific dial color. This version highlights the architectural qualities of the design in a different light.