Otsuka Lotec: Jiro Katayama’s Authentic Japanese Watchmaking, From No.5 KAI to the High‑Complication No.9
No matter how well-versed someone is in the world of horology, it never stops surprising with new stories of yet another original approach to design and craft. One of the latest stories is that of Jiro Katayama and his upcoming company, Otsuka Lotec. Let’s leap together into the world of this contemporary Japanese watchmaker, his timepieces, and the inspiration that led to them.
Brief history of Otsuka Lotec and founder Jiro Katayama
Jiro Katayama’s legacy is rooted in industrial design and a passion for mechanics. He is a self-taught watchmaker whose professional background stems from the automotive and product design industries, particularly the 20th-century industrial design field. His keen eye for detail, superb craftsmanship, and design background are embodied in each of the watches produced by the Otsuka Lotec manufacture.
Founder and master watchmaker Jiro Katayama at work in the Otsuka Lotec workshop.
The name of the company is, in fact, a compound word, where Otsuka stems from the part of Tokyo where the production facility is located, while Lotec is a modified transcription of low-tech. The brand name perfectly sums up the philosophy behind the authentic watches that emerge from Jiro Katayama’s original ideas and skilled craftsmanship: traditional craftsmanship meets contemporary ingenuity, driven by innovative ideas, continually broadening knowledge, and refining skills while creating at the small local production facility.
The watchmaking craft at Otsuka Lotec
Jiro Katayama’s interest in watchmaking began to take shape in 2008 when he purchased his first lathe to bring his own ideas to life. He initially learned about the production process through Google and YouTube. The self-taught approach and giving life to original ideas have been a constant presence ever since.
Meticulous manual assembly is a hallmark of Otsuka Lotec’s watchmaking process.
The master adheres to a hands-on manufacturing process, personally involved in every phase of watch creation, from brainstorming to operating the lathe and assembling the final product. The results are genuinely authentic watches that feature unique mechanical innovations, including retrograde displays and jumping hours, among others, all with pristine manual assembly and ultimate quality control of the entire production process.
A selection of Otsuka Lotec’s mechanical creations: No.7.5, No.6, No.5 KAI, No. 9 - each model exhibiting unique complications.
Due to this crafting approach, all Otsuka Lotec watches are produced in limited volumes. The entire production comprises approximately 500 pieces over 17 years, lending a note of exclusivity to the fortunate owners of individual watches. Additionally, the entire production is aimed at the Japanese market until the manufacturing capacity is strong enough to start offering watches outside of Japan.
Design Philosophy: Classic Industrial Meets Retro-Futuristic Style
Jiro Katayama draws his inspiration from old cameras, mid-20th-century analogue instruments and tools, such as pressure gauges. The overall radiance of the design is a combination of classic industrial style and futuristic elements, epitomizing a retro-futuristic style. Some of the key design elements include exposed screws, stepped bezels, wire lugs, and gauge-like dials, which result in a masculine aesthetic that emphasizes ruggedness and technical sophistication.
Key Otsuka Lotec Models: Past and Present
Eight models have emerged from the Otsuka Lotec workshop so far - all of which have vividly authentic looks and simple names. No. 5, No. 6, No. 7, and No. 7.5 are earlier models that were in production until 2022 and are now rarely available on the second-hand market.
No.5 - the debut model featuring regulator-style rotating disc displays.
No. 5 is the first-ever Otsuka watch to hit the market. It’s a regulator watch that features rotating hour and minute discs at the top and bottom of the dial. There is very scarce technical data available on it, and it can only be deduced from the second in line, No. 6, that they share the following features: SUS303L stainless steel case and mineral glass. There are two more things these two watches have in common: a data complication and a 2 O’Clock crown.
No.6 caseback - showcasing the modified Miyota 9015 movement.
No.6 came out in 2015. Apart from the features it shares with No. 5, it is a retrograde watch with a distinct dial that bears a strong resemblance to an analogue meter or pressure gauge. Finally, it comes with a transparent caseback, allowing close-up views of the modified Miyota 9015 automatic movement’s operation.
The aesthetics of No. 7 and No. 7.5 stem from the same design inspiration: old movie cameras. Turret-shaped windows on display hours and minutes on No.7 and, additionally, seconds on No.7.5. Both watches feature jumping hour mechanisms and acrylic fisheye lenses, and use the same case and glass materials as their predecessors, No.5 and 6, as well as transparent casebacks and mechanisms.
No.7 and No.7.5 - retro camera-inspired displays with jumping hour mechanisms.
No. 5, No. 6, and No. 7.5 have been improved over the years. No. 6 and No. 7.5 were released as upgraded models in 2023, while No. 5 KAI was introduced at the beginning of 2025. Innovations that all three upgraded models share are SUS316L Stainless steel cases and sapphire crystal glass.
No. 6 now features beveling on both sides of the minute and hour hands, as well as on the bezel and the heads of the dial screws. Additionally, the lugs that secure the bezel were relocated to the backside.
No.7.5 - enhanced finishing - custom sapphire fisheye lenses and upgraded stainless steel cases.
No. 7.5 features custom-made sapphire crystal fisheye lenses and is powered by the Miyota 82S5 movement, along with an In-house jumping hour module. Additionally, it features an enhanced case finish, achieved through the implementation of straight graining and sandblasting.
Revised No.5 KAI - satellite hours with three rotating numeral discs, right‑side minutes track, and visible ball bearings on the dial.
No. 5 KAI follows in the footsteps of its predecessor’s case design, with several improvements made to both the exterior and interior. First, KAI is a satellite hour watch sporting three rotating numeral disks. Second, the hour and minute display is on the right side of the dial for improved readability and design balance. Consequently, the crown was moved to the 6 O’Clock position. Lastly, No.5 KAI features a specially made ball bearing for the hour disk, as well as the world’s smallest 1.5 mm diameter ball bearing for the seconds disk.
The latest Otsuka Lotec watch, No.9
The unusual aesthetics captivate at first glance with No.9, as well. It's fresh from the oven, released just a couple of days ago. And potentially marks a new direction for Otsuka Lotec, judging by its features.
No.9 - combining jump hour, tourbillon, hour striking gong, and power reserve in one design.
A result of 9 years of development, No.9 displays a higher complication nature. It’s a jump hour watch, coupled with several complications: rewinding minutes, a Tourbillon, hour striking, and a power reserve. All packed in a compact 48mm diameter and 13mm thick stainless steel case, with sapphire crystal glass and a solid caseback.
Another notable novelty is that No.9 is powered by Cal. SSGT mechanism developed by Jiro Katayama. It’s an in-house movement with some elements taken from the ETA/Unitas Cal. 6498.
Cal. SSGT - Jiro Katayama’s in-house movement, with roots in ETA/Unitas 6498.
Dial, inspired by old Japanese power meters, is particularly interesting. The right side shows time, while an hour striking gong occupies the left part. That’s a lovely homage to industrial design, where each component radiates the feeling of industrial machinery.
With a listed price of $108,000, Otsuka Lotec No. 9 clearly aims high, and to an entirely new ballpark that other models in its catalog do not. Time will tell if such a move will be adequately rewarded.
Recognized and rewarded performance and technical excellence
Diligent construction approach and top-level craftsmanship, paired with authentic design, cannot go unnoticed in the horology world. Although Otsuka Lotec has focused on the Japanese domestic market, in our modern times, good news travels even faster. It wasn’t long before word of the new Japanese watchmaking company spread from its rising domestic user and fan base, reaching an international level. Next to growing interest from general fans, the horology critics quickly became aware of the Otsuka Lotec’s catalog and closely monitored its development.
GPHG 2024 honor: Jiro Katayama, founder of Otsuka Lotec, accepts the Challenge Watch Prize at the 24th awards ceremony.
Two renowned awards followed as a result of all these factors. Jiro Katayama received recognition as a “gendai no meiko” (contemporary master craftsman) from the Japanese labor ministry in November 2024. Just five days later, Otsuka Lotec's Model No.6 won the prestigious "Challenge Watch Prize" at the GPHG awards in Geneva. Finally, the No.7.5 model received the iF Design Award 2024 for excellence in product design.
Why Watch Enthusiasts Should Care About Otsuka Lotec
As short as possible, for the construction diligence, originality, consistency in direction, and quality. It’s clear by now that each Otsuka Lotec model embodies the brand’s DNA and follows in the footsteps of constant innovation. These traits have been recognized by both fans and professionals, which has yielded the brand’s growing reputation and promising future prospects.
Another intriguing aspect that raises additional interest in what comes next from Otsuka Lotec manufacture is the emphasis on analogue experience in a prevailing touchscreen world. Furthermore, limited production, the current Japanese domestic market focus, combined with unique design and mechanical quirks, contribute to exclusivity and enhance the collectors' value of Otsuka Lotec watches produced to date.
In the end, authenticity matched by ultimate craftsmanship and continual improvement in execution and design is a proven recipe for ultimate success in the horology world. Otsuka Lotec has clearly taken the right path, carefully taking every step along the way, staying true to the original ideas and visions of master Jiro Katayama. Let’s all enjoy the journey.
Written by S.K., images by others as noted
External references:
- Otsuka-lotec.com
- @Jiro.Katayama
- Ōtsuka Lōtec Debuts the New No. 9, an Experiment in Haute Horology
- Watchmaker Jiro Katayama, the Man Behind Otsuka Lotec and Japan’s new Sensation
- Why This Brand You Can Only Get In Japan – Ōtsuka Lōtec – Won GPHG's Challenge Prize
- Hands-On With The Otsuka Lotec No.7.5 - A Jump-Hour Watch With Monochromatic Swagger
- Grand Prix d'Horlogerie de Genève's post
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