MB&F HM12 The Guardian: Horological Masterpiece Unveiled

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What is the MB&F HM12 The Guardian? An object that tells the time, an objects that express a philosophy, or something that refuses categorisation entirely? Or maybe all…When Maximilian Büsser founded MB&F in 2005, the premise was audacious: build a horological concept laboratory, not a watch brand. Twenty years and over twenty in-house calibres later, the Geneva independent has accumulated ten Grand Prix d’Horlogerie de Genève awards, including the coveted Aiguille d’Or, and an audience that has grown to expect the unexpected.

Yet even within that context, HM12 The Guardian lands as something genuinely new. It is not a wristwatch with a display stand. It is a total horological concept, one piece in two bodies, a robot with a watch for a brain and nearly 1,500 components working as one unified mechanical organism. The ambition alone deserves attention. The execution demands scrutiny.

Twenty Years of Roots, One Machine to Rule Them

Originally conceived to mark MB&F’s 20th anniversary, HM12 took considerably longer to realise than anticipated. What began as a celebratory project gradually expanded in scope and complexity until it became the ideal object to launch the brand into its third decade. For Büsser, the starting question was deceptively simple: what if a robot’s head were a watch? He framed the concept and stepped back, handing architectural ownership to designer Max Maertens, who spent four years iterating, drawing, modelling in 3D, printing prototypes and refining proportions until the proportions aligned with the narrative.

The creative significance of HM12 extends beyond its technical ambition. For the first time in MB&F‘s history, an Horological Machine is conceived without long-standing collaborator Eric Giroud, whose contribution to the brand’s visual language has been foundational. Instead, the duo of Maximilian Büsser and Maximilian Maertens, two Maxes, takes full creative ownership of an HM for the first time. That handover alone signals a generational shift inside the atelier.

A Face That Tells Time

The dial of HM12 operates as a face before it operates as a time display, and that hierarchy is intentional. Two rotating discs occupy the position of eyes: instantaneous jumping hours on the left, trailing minutes on the right. The information moves on the discs while the reading point stays fixed, producing a display that feels both futuristic and strangely legible. Above, where the forehead would be, a flying tourbillon sits fully exposed, visible from the front and laterally through the upper sapphire crystal at 12 o’clock. Below, one face of the double-sided micro-rotor, shaped in the form of the MB&F battle-axe, occupies the position of the mouth. Super-LumiNova highlights activate the watch and, remarkably, the robot companion itself under UV light.

The defining feature of the dial architecture, however, is the face shield system. Actuated via the left crown, two shields move linearly across the face of the watch, allowing the wearer to expose or conceal the dial at any point between fully open and fully closed. The crown itself is declutching: once the shields reach their endpoint, it disengages automatically. This system involves over 200 dedicated components, a figure that exceeds the total component count of many conventional mechanical watches. The finishing of the shield mechanism reflects this seriousness: chatons, polished wheels and inward angles speak the language of traditional haute horlogerie rather than novelty engineering.

The Engine: Two Faces of One Calibre

Turn HM12 over and the language shifts entirely. Where the dial side speaks in science fiction, the caseback opens onto something far closer to a classical Legacy Machine aesthetic. The in-house calibre, developed entirely at MB&F over four years, counts 646 components and 86 jewels, with a power reserve of 84 hours via automatic winding through a double-sided micro-rotor. The architecture of the movement follows the contours of the case rather than imposing its own geometry, producing a result that feels open, balanced and symmetrical.

The finishing on the movement back is where the calibre asserts its haute horlogerie credentials most confidently. Bridges are softly curved and hand-finished throughout. The mainplate carries a grained surface. Twin barrels feature snailed finishing. Polished angles appear across the bridges alongside frosted surfaces. Most remarkably, the rear rotor is decorated with a guilloché dome executed with the direct involvement of Kari Voutilainen and his team. Applying guilloché to a curved, spherical surface rather than a flat plane is an exercise of considerable technical difficulty; Voutilainen’s expertise in this area, which has shaped some of the most admired finishing in contemporary independent watchmaking, brought the precise rigour required for this exercise. The result is a rotor that commands attention from the caseback even before the flying tourbillon, visible through the rear sapphire, draws the eye upward.

The Case: Sapphire, Titanium, and Considered Geometry

The case of HM12 is crafted from Grade 5 titanium and comprises 84 components. Three sapphire crystals, positioned on the front, back and at 12 o’clock looking directly onto the tourbillon, allow light to enter from multiple angles and animate the movement from every viewing position. The skull of HM12, as MB&F describes it, is largely sapphire, transforming the case into a transparent volume that reveals the movement rather than merely housing it.

Mobile lugs at 12 o’clock and fixed lugs at 6 o’clock govern the strap architecture, which uses a quick-release system that allows the watch to detach from the wrist entirely and mount directly onto The Guardian robot via a secure clipping mechanism. Dimensions measure 49.3 mm in length, 43.6 mm in width, and 13.8 mm in height, figures that position it squarely in the territory of sculptural wristwatch rather than daily wear, which is precisely the point. The strap itself, produced by Manufacture Jean Rousseau, stores neatly inside a hidden drawer integrated into the robot’s base when the watch occupies its companion.

A Concept Delivered, a Third Decade Opened

The Guardian robot, developed by L’Epée 1839, stands 38.2 cm tall, weighs approximately 15 kg including its base, and incorporates 755 components. A mechanical thermometer sits at its chest. One arm carries a loupe calibrated to inspect the movement; the other holds a detachable UV torch designed to activate the Super-LumiNova on both watch and robot. This is not decoration. It is a working system built around a working watch.

HM12 The Guardian is produced in three limited editions of twelve pieces each: blue, purple and green, totalling thirty-six pieces in existence across the entire planet. The retail price is set at CHF 280,000 before taxes. That figure, significant as it is, buys entry into a concept that has consumed four years of development across two Maxes, a flying tourbillon, a 200-component complication in its own right, a guilloché dome finished by one of watchmaking’s most respected craftsmen, and a 38-centimetre mechanical companion with its own tools. In the context of what it represents, the price is not the first number that springs to mind. The number that lingers is 1,500, the total components across watch and robot combined, each one the product of MB&F doing what it has always done best: refusing to let the idea stop before the object is complete.

MB&F HM12 The Guardian Technical Specifications

HM12 is crafted in three editions of 12 pieces each: Green, Blue and Purple – CHF 280,000 + VAT

Movement

In house automatic movement, double winding rotor
Flying tourbillon
Instantaneous jumping hours
Trailing minutes
Shield function
Power reserve: 84 hours
646 components
86 jewels

Case

Grade 5 titanium
84 components
Super-LumiNova highlights
Mobile lugs at 12 o’clock
Fixed lugs at 6 o’clock
Three sapphire crystals, top, bottom, and at 12 o’clock with view on the tourbillon
Dimensions: Length 49,3 mm, Width 43,6 mm, Height 13,8 mm

Strap