SB10 JUMPING HOUR 50–50 Grind

The Balance of Time

An idea born from a watchmaking dream

For its tenth anniversary, Sartory-Billard unveils the SB10. A watch born from a project once considered impossible: the SB08.

Presented in 2024, this concept watch explored an extreme architecture, combining multi-sapphire construction, advanced complications, and a radical vision of time display: a wide aperture for the hours, a fluid reading of the minutes, and a central surface entirely freed from the traditional dial.

Its development would have required an investment exceeding one million euros. It could not exist. And yet, its essential idea endured: to offer a clear, almost poetic reading of time, grounded in material.

“I couldn’t let go of what defined the soul of the SB08,” explains Armand Billard. “That wide hour aperture, that fluid minute display, and above all that liberated surface - a true blank page for creativity.”

The SB10 is that idea made possible - not a simplification, but a distillation, faithful to the Sartory-Billard DNA.

Watchmaking & skateboarding

For many, skateboarding in the 1990s evokes a distinct moment in time. Afternoons spent in the streets, improvised spots, boards marked by use. A practice lived freely, without structure, shaped by a strong visual and cultural identity. This edition draws from that memory, echoing a generation that grew up with these codes and this mindset.

On the 50-50 Grind Edition, the cabochon is made from genuine skateboard elements, directly sourced from decks and their grip surface. The cut of the wood reveals the layered plywood construction, its lines, tonal variations, and natural irregularities, while the rest of the cabochon carries the texture of grip tape, the granular surface designed for traction. The result is a strong visual contrast, and each piece presents a unique configuration, assembled by Armand Billard.

Each cabochon is therefore different, with its own lines, tones, and balance, giving every piece its own character.

Context and craft

The development of this edition was carried out in collaboration with the Skateboard Museum of Geneva. Its founder and curator, Jim Zbinden, was involved throughout the project, from early research to final decisions, bringing his perspective to the selection of the skateboard decks used in the 50-50 Grind project.

The museum brings together pieces spanning several decades of skateboard history. Its presence in Geneva, a city historically associated with watchmaking, gives this edition an unexpected grounding.

The cabochon thus becomes a meeting point between a material rooted in skateboarding and a horological construction. The name “50-50 Grind” refers to an iconic skateboarding trick, in which the board slides along an obstacle in balance. A movement that appears simple, yet is fundamental in practice. This idea of balance is reflected in the watch, between raw material and precise horological construction.

The cutting of the decks was entrusted to Martin Krause, a German luthier accustomed to working wood with precision. A watch enthusiast and collector of Sartory-Billard pieces, Martin contributed his expertise and dexterity to carry out the delicate and unusual wood cuts required for this project.

Reinventing the jumping hour

Jumping hour watches offer a unique mechanical spectacle: an instantaneous, sharp, almost theatrical change. But they are often difficult to read, with small apertures and limited visibility.

The SB10 takes a different approach. At six o’clock, a large aperture reveals the hour on a sapphire disc. This opening has been deliberately enlarged to provide immediate legibility—a conscious, almost personal choice.

“I’m 50 years old, I need to see the time clearly,” says Armand Billard.
The numeral appears in an unusual scale for a jumping hour watch, nearly twice the size of some traditional references. The numerals, specifically designed for Sartory-Billard by typographer Simon Schmidt, enhance readability through a balance of modernity and timelessness.

A simple movement of the wrist is enough—the time appears effortlessly.

Without hands

The SB10 has no hands.

Time is entirely displayed through two ultra-thin sapphire discs, approximately 0.2 mm thick that seem to disappear into the light.

The hour disc jumps 30 degrees every 60 minutes, instantly revealing the next numeral. This mechanism creates a strong visual effect, almost cinematic: a precise instant, a shift, a beat.

The minute disc evolves continuously around the cabochon, creating a contrast between time that jumps and time that flows.

Two rhythms coexist: one discreet and punctual, the other fluid and continuous. This duality defines the unique character of the SB10.

Minutes in orbit

The minutes are indicated by a sapphire disc completing a full rotation every sixty minutes. Around the cabochon, a peripheral ring coated with Super-LumiNova BGW9 traces the passage of time. This luminescent material, known in watchmaking for its stability and intensity, absorbs light during the day and releases it in the dark.

A red marker crosses this luminous ring, indicating the minute precisely, offering immediate and contrasted legibility in daylight.

But it is at night that the SB10 reveals another dimension. The ring glows with an intense turquoise light, forming a continuous halo around the cabochon. The light seems to float, suspended around the central material.

Time is no longer just read—it becomes atmosphere: a slow, silent, almost hypnotic rotation, a luminous circle in motion—a nearly celestial phenomenon on the wrist.

Between watchmaking and jewellery

The SB10 has no dial. A cabochon replaces it, a polished, sculpted surface borrowed from jewelry, with no mechanical function.

This piece becomes the center of the watch, an element brought from outside, like a gemstone set onto the case—not to indicate time, but to give it presence.

Its surface captures light, but also the eye and the gesture. The cabochon is not only meant to be seen—it is designed to be touched. Polished, crafted, sometimes textured, it creates a physical, almost instinctive relationship with the watch.

The cabochon is not interchangeable. It is an integral part of the watch, creating an intimate link between the object and its owner. Like a jewel, it exists through time and use.

It is a watch to be both looked at and touched, where material naturally invites gesture, where the finger follows the surface to feel its relief and temperature.

The watch becomes a meeting point between the rigor of watchmaking and the freedom of material.

The watch

Beneath this refined architecture lies a coherent mechanical construction.

The SB10 is powered by the automatic G100 calibre from La Joux-Perret, chosen for its reliability and 55-hour power reserve, paired with a patented jumping hour module ensuring a sharp and precise jump.

Both hour and minute discs are made of sapphire and housed within a 39.5 mm stainless steel case (316L), whose proportions provide balance, legibility, and openness.

Each technical choice serves the same vision: clarity, coherence, and evidence.

The 2026 production plan is, at this stage, limited to 300 SB10 pieces, each individually numbered.

About Watchmakers United

Watchmakers United (WU) is the first retail space in Geneva dedicated exclusively to independent watchmakers, with a flagship boutique at Rue Pierre Fatio 5 (opened in January 2024) and a new location in Monaco. WU provides independent brands with physical retail presence, editorial positioning, and access to a curated international collector network.

About the Skateboard Museum of Geneva

The Skateboard Museum of Geneva is one of the very few institutions of its kind in the world dedicated to the history, culture, and material heritage of skateboarding. Founded and curated by Jim Zbinden, it preserves decks, equipment, photography, and archival material spanning from the origins of the sport to the present day. Its presence in Geneva — a city better known for watchmaking and diplomacy than street culture — is both unexpected and significant. The museum serves as a reference point for skaters, collectors, and anyone interested in the evolution of a discipline that has shaped design, music, fashion, and urban life worldwide.

Technical specifications

Name: SB10 50-50 Grind
Case: 39.5 mm stainless steel, alternating polished and satin finishes
Thickness: 11.5 mm
Lug-to-lug: 44 mm
Movement: Swiss automatic La Joux-Perret movement with 55-hour power reserve, paired with a patented jumping hour mechanism
Water resistance: 80 meters
Strap: Sartory-Billard rubber strap, available in multiple colors (white, grey, black, blue, red, brown, green)
Price: CHF 3,700 excluding taxes

Limited to 50 numbered pieces.
Available exclusively through Watchmakers United.
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SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
  • SB10 JUMPING HOUR 50–50 Grind
SB10 JUMPING HOUR 50–50 Grind

SB10 JUMPING HOUR 50–50 Grind

CHF 3,700 excluding taxes
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Technical Specifications

Name: SB10 50-50 Grind
Case: 39.5 mm stainless steel, alternating polished and satin finishes
Thickness: 11.5 mm
Lug-to-lug: 44 mm
Movement: Swiss automatic La Joux-Perret movement with 55-hour power reserve, paired with a patented jumping hour mechanism
Water resistance: 80 meters
Strap: Sartory-Billard rubber strap, available in multiple colors (white, grey, black, blue, red, brown, green)
Price: CHF 3,700 excluding taxes

Limited to 50 numbered pieces.
Available exclusively through Watchmakers United.