Introduction
Originally moving into watchmaking in 2008 after studying automotive design, Jiro Katayama, a Tokyo-based watchmaker and designer, draws his inspiration from the realm of industrial world where his career originally started. Incorporating automotive design details and an industrialized steampunk aesthetic, Katayama’s timepieces, offered in limited runs only in Japan through his brand Otsuka Lotec, are some of the most visually distinctive and unique watches within the modern realm of indie watchmaking. Winning the recent Challenge Watch Prize in 2024’s GPHG awards with the No. 6, the watches that we have here are three examples of the brands most sought-after models, their No. 5, No. 6, and No. 7.5.
Introduced in late 2024 and officially in production in 2025, the No. 5 features a unique 40.5mm brushed stainless steel construction with large lug hoods that flow down to short lugs, and up to a thin bezel that surrounds what is a wonderfully unique satellite hour display that builds on Otsuka Lotec’s reputation as a watchmaker exploring different types of time display. As with their other watches, the No. 5 is a wonderfully utilitarian watch that combines a rich sense of design with a fun take on a unique method of displaying the time to create a truly exceptional timepiece that is without equal in today’s watch market.
Winning the Challenge Watch Prize in 2024’s GPHG awards, the No. 6 has quickly become Otsuka Lotec’s most revered watch. Boasting a brushed stainless steel design with exposed screws, a stepped bezel, wire lugs, and a large monochromatic retrograde time display, the resulting timepiece is reminiscent of the pressure gauge on a car or a hygrometer.
Launched in 2021 and iterated upon with some changes in 2023, the No. 7.5 features a unique 40mm brushed stainless steel construction with wire lugs that boasts a unique display inspired by vintage 3-lens turret 8mm cameras, as shown by its trio of lenses that sit above its hour, minutes, and seconds display. Boasting a jump-hour function, the No. 7.5 is a wonderfully utilitarian watch that combines a rich sense of design with a fun take on a unique source of inspiration to create something truly exceptional timepiece that is without equal in today’s watch market.
Loupe This Scorecard
Grade
M 9.5
Status
Vetted & Approved
Included
Full sets with guarantee cards
Est. value range
$12,000 – $15,000
The Details
Brand
Otsuka Lotec
Dimensions
No. 5 = 40.5mm x 12.2mm; No. 6 = 42.6mm x 11.8mm; No. 7.5 = 40mm x 11.2mm
Model
No. 5, No. 6, and No. 7.5
Movement
No. 5 = Automatic Miyota cal. 90S5; No. 6 = Automatic Miyota cal. 9015; No. 7.5 = Automatic Miyota cal. 82S5
Reference
P05, P06, P75
Bracelet
Leather strap (all three)
Year
2025 (all three)
Condition
Like new
Material
Stainless steel (all three)
Included
Watch, box, and papers for all three examples
Dial Color
Silver (all three)
THE NO. 5
Conforming to Otsuka Lotec's decidedly nonconformist aesthetic, the Kai's satellite hour display (powered by their in-house movement module), dominates the timepiece thanks to the thin bezel that surrounds it and large sapphire box crystal that stands above it.
THE NO. 6
Designed to emulate the gauges that adorn the dashboards of cars and industrial equipment, the No. 6's monochromatic silver dial features a retrograde minute and hour hand along with exposed screws that further feed into its steampunk aesthetic.
THE NO. 7.5
Featuring a unique jump hour display whereby its hours, minutes and subtle running seconds displays are all shown within their own windows, the No. 7.5's dial is decidedly industrial and utilitarian.
Condition
All three watches are in overall like-new condition. The cases show only light signs of wear or handling. Each comes complete with box and papers. Cards are all dated mid 2025. Watches are all functioning and appear to be keeping good time.
Our Perspective
While Otsuka Lotec might be a Japan-exclusive brand, their unique approach to watchmaking and unusual designs have earned them plenty of plaudits around the globe, and so now their offerings are intensely sought-after, leading to all of their watches becoming instant hits, and opportunities to pick up three of their most desirable watches all at once certainly don't come up often.
Eric Ku
Co-founder
