Introduction
Few modern independent watchmakers have carved out a design language as distinctive as Jiro Katayama. Before founding Otsuka Lotec in 2008, Katayama trained as an automotive designer, an influence that continues to shape every watch he creates. Rather than drawing inspiration from traditional Swiss watchmaking, his creations celebrate industrial machinery, precision instruments and mechanical engineering, resulting in watches that feel more like beautifully executed scientific devices than conventional wristwatches. Produced in extremely limited numbers and available almost exclusively within Japan, Otsuka Lotec has rapidly become one of the most sought-after names in contemporary independent watchmaking, a reputation cemented by winning the Challenge Watch Prize at the 2024 Grand Prix d'Horlogerie de Genève.
Introduced in 2021 and subtly refined in 2023, the No. 7.5 perfectly encapsulates Katayama's unconventional approach to displaying time. Inspired by the three-lens turret found on vintage 8mm film cameras, the watch replaces a traditional dial with three individual apertures displaying jumping hours, wandering minutes and running seconds beneath domed sapphire lenses. The result is both highly mechanical and remarkably intuitive, transforming the simple act of reading the time into an engaging visual experience. Housed in a compact 40mm stainless steel case with elegant wire lugs and powered by a modified Miyota automatic movement, the No. 7.5 demonstrates how originality and functionality can coexist in one of today's most distinctive independent designs.
Loupe This Scorecard
Grade
M 10
Status
Vetted & Approved
Included
Box and papers
Est. value range
$4,000 – $6,000
The Details
Brand
Otsuka Lotec
Dimensions
40mm
Model
No. 7.5
Movement
Automatic Miyota calibre 82S5
Reference
P75
Bracelet
Leather strap
Year
2026
Condition
New
Material
Stainless steel
Included
Box and papers
Dial Color
Silver
THE DIAL
Rather than a conventional dial, the No. 7.5 presents the time through three separate sapphire-covered apertures inspired by vintage 8mm movie cameras. The jumping hour, retrograde-style minute display and discreet running seconds create an engaging mechanical display that is unlike anything else in contemporary watchmaking.
THE CONSTRUCTION
The brushed 40mm stainless steel case is paired with elegant wire lugs that reinforce the watch's industrial yet understated character. Every surface reflects Jiro Katayama's function-first philosophy, allowing the unusual display to remain the clear focal point while ensuring exceptional comfort on the wrist.
TIMING MACHINE READOUT
This reading was taken (crown down) with a ONEOF Accuracy Boutique Edition timing machine at time of cataloging. It is provided as a courtesy only, and shall not be construed as a warranty or guarantee of any kind. Please refer to our terms and conditions of sale for more information.
Condition
Watch is in new condition.
Our Perspective
The No. 7.5 perfectly demonstrates why Otsuka Lotec has become one of the most exciting names in independent watchmaking. Rather than pursuing complexity for its own sake, Jiro Katayama has created a genuinely original way of displaying time that is both playful and highly functional. Produced in very limited numbers and rarely seen outside Japan, the No. 7.5 is a compelling reminder that some of the most innovative ideas in contemporary horology are emerging far beyond the traditional centres of Swiss watchmaking.
Eric Ku
Co-founder
