According to that NYT article, all of their mechanical watches are made there at Seiko's mountain retreat.
full article artfully pasted:
SHIZUKUISHI, Japan — Tucked in the mountains of Iwate Prefecture, more than two hours north of Tokyo by bullet train, is the small town of Shizukuishi, known to watch fans as the cradle of mechanical watchmaking in Japan. That’s because it is the home of the studio that makes several brands of Seiko mechanical watches, including Grand Seiko, the company’s luxury marque.
The quiet setting was one reason the town was chosen in 1970 for Seiko operations, said Yoshiaki Hayashi, managing director of the local operation, Morioka Seiko Instruments Inc., which includes the Shizukuishi Watch Studio: “It enables our craftsmen to concentrate on detailed work.”
“Iwate people are known for being precise,” he added, referring to the ironware-making tradition of the Sanriku Coast. “They tend to fit the requirements to become craftsmen.”
Seiko should know: It is one the largest employers in this town of about 17,000 residents. Part of the large factory building houses Morioka, its lightning-fast automated assembly lines producing quartz watches (the technology on which Seiko has built its prosperity and which continues to develop). But that’s a stark contrast with Shizukuishi’s more artisanal environment, just down the hall.
The mix echoes Seiko’s complex structure (some visitors are shown a half-hour PowerPoint presentation on that subject alone). Founded in 1881 as a watch and clock shop in central Tokyo, it now is called the Seiko Holdings Corporation, with scores of companies and hundreds of products, most related to timepiece technology.
Seiko’s relationship with mechanical watches is similarly complicated: It introduced the Grand Seiko — what a company timeline calls its “signature piece” — in 1960. Then it decided to focus on inexpensive quartz models and stopped making mechanical timepieces entirely from 1973 to 1988, the period that the industry still calls the Quartz Crisis, resuming production only when mechanical watches began to regain public acclaim for their craftsmanship and style.
As its output grew, Seiko established the Shizukuishi workshop in 2004, and the Grand Seiko line — its mechanical watches, Spring Drive models and quartz collections — were rolled out internationally in 2010. (The line became an independent brand in 2017 and its first company, Grand Seiko Corporation of America, was established in October to market the models.)
One of the Shizukuishi hallmarks is the mirrorlike glow of its watch cases and bracelets, the result of an exacting technique called zaratsu, used by Seiko since the 1950s to create polished, distortion-free surfaces. Also, its dial patterns are inspired by the mountains and, in the winter, the snowy environment of Shizukuishi.
"While Seiko’s midmarket quartz watches are made at several locations, all the company’s mechanical timepieces are made and assembled in Shizukuishi, from the tiny parts churned out in oil-filled baths (parts so minuscule their shape can be seen only through a microscope), through processing, assembly and adjustment, and on to testing (more than 400 hours for each timepiece)."
Employees of all ages, including the 90 master craftsmen and women of Shizukuishi, mill about in the various production rooms. They wear cotton factory uniforms — gray or black trousers and jackets of various colors. (On a recent day, Mr. Hayashi wore a pink jacket, but he noted that the colors didn’t have any special meanings.)
The organization of the Shizukuishi factory’s production lines resembles that of its Swiss counterparts, but the atmosphere is singularly Japanese. Visitors entering the building must replace their shoes with a pair of company-provided plastic slippers. And twice each workday, around 10 a.m. and 3 p.m., employees absent-mindedly stretch, bend and jump, the calisthenics called radio taiso that are done in many Japanese factories.
“It’s refresh time,” Mr. Hayashi said as the factory loudspeakers began to broadcast the instructions, done in song and accompanied by piano notes.
The watchmaking process culminates in the assembly room, a clean space that requires a head-to-toe cream-colored jumpsuit with an attached cap and shoe covers. Once visitors are outfitted, they pass through an airlock, which blows a gust of air over them to get rid of as much dust as possible.
This room is where the mechanical watches really come to life. It has large windows overlooking lush greenery and views of Mount Iwate in the distance, a place of worship in both the Buddhist and Shinto religions. Rows of elite technicians, who wear white coats over their jumpsuits and white hats that look a bit like a Jiffy Pop pan when the popcorn is ready to eat. They work in silence, assembling and adjusting watches at their desks, which are customized by the traditional woodworking business Iwayado Tansu in Iwate and finished with an urushi lacquer.
The studio has its own system of ranking a craftsman, called meister in the German manner: bronze, silver and, at the pinnacle, gold. Only six men now hold the gold designation and, to retain it, they must pass a test every two years.
One of them, Katsuo Saito, 50, is an authority on assembling the Calibre 68 movements for the Credor mechanical watch line.
“The movement assembly is nurtured by intuition. I use my intuition to adjust,” he said as he put the finishing touches on a movement. “You have to constantly adjust while you’re assembling a watch movement; otherwise you have to go back to the start. When I put the final parts together, it’s the moment the watch begins its life.”
As a team, the workers assemble 300 to 400 mechanical watches a month. They share all the tasks.
Sachie Kudo, 44, is the only woman working in the assembly room. She is a team leader for the adjustment process of automatic movements for women’s watches.
“A lot of workers were involved in making these watches, and this is the final stage where I assemble these parts, imbued with their spirits and emotions, and shape them into a watch,” she said. “So, I am nervous and I always want to assemble better ones.”