YEMA Senans Grande Lune: the moon stays still, the shadow moves

YEMA · Senans Grande Lune CMM.22

The model in detail

Meet the watch

The moon at seven o’clock does not travel across this dial. The luminous sculpted element stays in place while a two-lobed mechanical shutter gradually covers and uncovers it. That reversal makes the YEMA Senans Grande Lune more interesting than an ordinary moonphase window: you watch a shadow cross a small celestial body rather than a picture emerge from beneath the dial. This is the first model in the new Senans collection and YEMA’s first moonphase watch.

The lunar element is made from a three-dimensional block of Grade X Super-LumiNova using Globolight technology. Its crater pattern is visible by day; after dark, the material itself glows. It works because the lume explains the complication instead of merely decorating the hands. The shutter follows the slow lunar cycle, however, so do not expect a continuous show like a tourbillon. These watches suggest a different ritual: returning to the dial and noticing how it changes from day to day.

There is plenty of texture around the moon: a grain-shaped central pattern, circular brushing on the outer sector and applied markers of alternating lengths. The centre references Fibonacci spirals. I like the way the large asymmetric opening disrupts the order without destroying it: the outer scale preserves a clear route for reading the time. Blue looks like the calmest backdrop for this miniature performance. Still, slender polished hands above intricate relief need checking during a fitting: promotional lighting cannot replace ordinary indoor light.

Details and limitations

Inside is the automatic CMM.22 with a micro-rotor. Its small winding weight sits within the movement architecture, avoiding the need to place a large full-sized rotor above the bridges. YEMA used the 3.7 mm CMM.20 as its foundation and added the moonphase complication with less than one millimetre of additional height. This is engineering with a visible consequence: an expressive display has not required turning a dress watch into a tall instrument. Quick moonphase adjustment through the crown is also more useful to an owner than another decorative inscription.

Before ordering, ask YEMA to confirm the CMM.22 power reserve: the current official collection page does not state it. Autonomy matters especially in a moonphase watch: after it stops, you must restore the phase as well as the time. If you wear it only at weekends, convenient adjustment becomes part of the ownership experience rather than a minor line in the instructions. The checked page also gives no interval for accumulated moonphase error. The size of the moon tells you nothing by itself about its calendar accuracy.

The 38.5 mm steel case looks like a sensible frame for the large moonphase opening. YEMA’s current page specifies an 8.70 mm case thickness and a 46 mm lug-to-lug distance. The stepped polished bezel adds depth, while brushed flanks keep the whole case from becoming a single mirror. Importantly, Monochrome describes the 8.7 mm measurement as excluding the domed crystal: it should not automatically be taken as the watch’s total height. The double-domed sapphire deserves a side-on look, particularly if easy clearance beneath a tight cuff matters.

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The leather strap emphasises the model’s intimate character; the Milanese bracelet adds another metallic texture. YEMA gives the bracelet quick-release fittings and a sliding clasp for adjusting its length. Lug width is 20 mm. Water resistance is rated at 50 metres, but that is no reason to treat a leather strap as swimming equipment. Of the two options, I would start with leather: it keeps the main conversation between the dial’s relief and the moon rather than between several shiny surfaces.

As of November 8, public ordering is still ahead: YEMA has scheduled it for November 11, 2026 at 16:00 CET, with shipping beginning in the first week of December. Production is limited to 200 examples of each colour: blue, black and champagne. The checked US page for the blue model on leather shows US$2,790; that is not a calculation of the final delivered cost to Uzbekistan. Senans is primarily a watch for someone who enjoys unusual displays. Its strength is that the lunar mechanism defines the whole appearance rather than hiding as an extra function.