Introduction
Few independent watchmakers have forged such a distinctive identity in such a short period as Jiro Katayama. After studying automotive design and working in industrial design, Katayama founded Otsuka Lotec in 2008 with the aim of creating watches inspired not by traditional Swiss horology, but by the functional beauty of machinery, cameras and precision engineering. Produced in extremely limited numbers exclusively in Japan, Otsuka Lotec's creations have developed a devoted international following, culminating in the brand receiving the Challenge Watch Prize at the 2024 Grand Prix d'Horlogerie de Genève for its No. 6.
Introduced in 2021 and refined in 2023, the No. 7.5 perfectly encapsulates Katayama's industrial design philosophy. Inspired by vintage three-lens turret 8mm movie cameras, its unconventional display replaces traditional hands with three separate apertures beneath prominent circular lenses. Hours are displayed via a jumping-hour complication, while the minutes and running seconds occupy their own dedicated displays, creating a remarkably intuitive yet entirely original method of reading the time. Housed within a fully brushed 40mm stainless steel case with distinctive wire lugs, the No. 7.5 demonstrates that originality need not come at the expense of practicality. It is an unmistakably modern independent watch whose engineering-led design sets it apart from virtually anything else being produced today.
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 with jumping-hour moduleLeather strap
Reference
P75
Bracelet
Leather strap
Year
2026
Condition
New
Material
Stainless steel
Included
Box and papers
Dial Color
Silver
THE DIAL
Inspired by vintage turret movie cameras, the dial replaces conventional hands with three individually framed displays beneath prominent circular lenses. The jumping-hour aperture is complemented by separate minute and running seconds indications, creating an industrial aesthetic that is both distinctive and surprisingly intuitive.
THE CONSTRUCTION
The fully brushed 40mm stainless steel case reflects Jiro Katayama's industrial design background, with every surface serving a functional purpose. Slim wire lugs soften the otherwise utilitarian construction, while the prominent sapphire lenses give the watch its unmistakable architectural character.
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.
Please note: The watch ticks at the time of cataloging, but timekeeping is poor and a service is recommended.
Our Perspective
The No. 7.5 is a perfect example of why independent watchmaking continues to captivate collectors. Rather than reinterpreting familiar designs, Otsuka Lotec has created an entirely original way of displaying time that draws inspiration from industrial machinery instead of traditional horology. Produced in very limited quantities and available only through Japan, it represents the kind of thoughtful, highly individual watchmaking that has rapidly established Jiro Katayama as one of the most exciting voices in contemporary independent horology.
Eric Ku
Co-founder
