To always findthe next way forward

About Us


We contribute to
a better world with
a craftsmanship
built on fairness.

Representative Director, President, and CEO, Kohsai Co., Ltd.

深沢 栄治 Eiji Fukasawa

Leads in market share thanks to a fusion of
artisan techniques and cutting-edge machining

Our company is a jewelry parts & foged ring jewelry manufacturer based in Yamanashi Prefecture, a region which boasts the highest production volume of jewelry in Japan. 
We hold 50% of the domestic jewelry parts market, with a notable 70% in earring clasps. In the jewelry area, our specialization in forged rings, often used in bridal-related areas, has led us to create products in keeping with our customers’ expectations.
It is no exaggeration to say that jewelry and other ornaments have a very long history, their origins coinciding with the birth of mankind.
Since ancient times, craftsmen all over the world have relied on their own hands and tools alone in creating jewelry pieces; however, we are capable of pursuing both quality and quantity simultaneously by applying cutting-edge machining to the refined techniques of our craftsmen.
Kohsai produces approximately 10 million pieces of jewelry parts annually and about 30,000 pieces of foged jewelry (as of 2019). Despite the traditional difficulty of manufacturing jewelry, we are able to provide a stable supply of both these and jewelry parts with some of the best productivity and technological capabilities in Japan.

Creating products that consider
our users, partners, employees, descendants, and the Earth

What we hold dear in the operation of our business is fairness throughout our business: for the users who wear our products, for our business partners, for our employees, for our descendants, and for the global environment.
In other words, we are committed to a business that is both eco-friendly and people-friendly, making sure not to impose undue burden.
As an example, we not only supply easy-to-use, durable products for users and business partners, but also use new materials to create jewelry that does not cause allergic reactions to the metal.
We provide our employees with improvements in time-efficiency and productivity, as well as lifelong education centered on management, SDGs, and other key topics.
And, for the future generations and for the Earth itself, we have joined the J-Credit scheme and are promoting energy-saving initiatives in accordance. In addition, we plan to recycle bullion mainly using urban mines and are working to integrate these into products.
We, as people living in the modern age, believe that it is essential to be fair to both people and the environment.
Through these initiatives, we seek to create a sustainable business, economy, society, and even global environment.

Building added value and becoming
the de facto standard for Japan and the world

We are promoting the use of AI in improving time efficiency, raising productivity, and supplying better products.
By pursuing automation of some of our production processes, we are pursuing not only an eased work environment for our employees, but also higher quality products.
As mentioned previously, jewelry has a long history, with a unique development path in each country; therefore, values and preferences in design will differ depending on the place and environment.
Therefore, success on the global stage is not an easy proposition.
However, by building added value with our sustainable product creation, and our fusion of technique and technology, we seek to supply jewelry and jewelry parts as the world’s de facto standard.
The path to that goal is expected to be steep and harsh, but we will contribute to the development of the world by proactively taking on challenges, from our home of Yamanashi, to Japan, and the global stage with products that only we can produce.


Combining craftsmanship and cutting-edge machining to provide both eco-friendly and people-friendly products

We have enabled mass production of our products while still pursuing quality thanks to our cutting-edge machining technology.
Today, we manufacture forged jewelry on a commercial scale, despite the difficulty in its processing, and we are responsible for manufacturing jewelry parts for well-known Japanese brands.
We are expanding our footprint out from Yamanashi, to Japan, and to the world, incorporating technology into our business whilst remaining mindful of sustainability.

Leveraging eco-friendly and people-friendly materials in a fusion of handmade technique and machining technology

What we pursue is safety, security, and ease of use.Plus, being kind to both people and the earth.Our unique technology allows us to produce under these constraints.

Reliable production capacity at our inhouse factory in Yamanashi

By consolidating our factory footprint not only in Japan, but here in Yamanashi Prefecture where our head office is located, we have complete control over everything from materials to finish.

50% of the jewelry parts and 70% of the earring parts markets

We have taken our patented blend of functionality, safety, and beauty and captured market share not only in Japan, but around the world.



To our valued customers,
we offer peace of mind, reliability,
pleasure, and excitement


Quality × Qualia
Our unique craftsmanship
brings contributions to our customers,
our society, future generations,
the Earth itself,
and the fulfillment and happiness of
all our employees.


For each and every person
around the world
who comes in contact with
jewelry, we want
to serve as a platform for
new, innovative value.


Since its founding in 1955, Kohsai continues its path forward,
as a jewelry manufacturer
headquartered in Kofu,

Trading Name: KOHSAI CO., LTD.
Businesses: Manufacture and sale of precious metal accessories / jewelry parts business / jewelry business (Listed on JASDAQ in October 1995)
Established: April 1967
Capital: 602 million yen
Representative: Eiji Fukasawa (Representative Director, President, and CEO)
Yuichi Kato (Outside Director)
Director (Audit and Supervisory Committee Member)
Makoto Suzuki (Outside Director)
Director (Audit and Supervisory Committee Member)
Kimikatsu Kanai (Outside Director)
Director (Audit and Supervisory Committee Member)
Satoshi Shibayama (Outside Director, Independent Officer)
Employees: 111 (55 men, 56 women)
Annual Sales: 2,733 million yen (fiscal year ending Jan 2019)
Transacting Banks: Mizuho Bank, Yamanashi Chuo Bank, Sumitomo Mitsui Banking Corporation, Japan Finance Corporation for Small and Medium Enterprise
Major Business Partners: Japanese major manufacturers, wholesalers/retailers, manufacturers within Yamanashi Prefecture, bullion dealers, jewelers, brands/national chains, ISHIFUKU Metal Industry Co., Ltd., ISHIFUKU JEWELRY PARTS CO.,LTD., others


3049 Ryuji, Kai City, Yamanashi Prefecture
TEL: +81-551-28-4181 (Switchboard)
FAX: +81-551-28-4672

Google Maps Link

Sales Office

Tokyo Sales Office

5-16-10 Ueno, Taito-ku, Tokyo
Kobayashi Bldg., 3F
TEL: +81-3-6806-0940

Google Maps Link

We were selected as a Driving Company for
the Regional Future by METI (Ministry of Economy, Trade and Industry)


A company selected for this honor is one that is currently, or is expected to in the future, proactively developing business that generates more added value by leveraging the unique characteristics of its region, powerfully driving its regional economy from economic ripple effects on business operators and others in its region.



Nobuo Fukasawa establishes Fukasawa Precious Metals Works in Yuda-cho, Kofu City, Yamanashi Prefecture


Factory constructed/transferred to Wada-cho, Kofu City, Yamanashi Prefecture, renamed Kohsai Kogei


Kohsai Kogei Co., Ltd. established with capital of 4.5 million yen


Established Futaba Factory in Futaba-cho, Kita-Koma-gun, Yamanashi Prefecture, to add new production facilities and launch operations in earnest


In response to business expansion, a new six-story factory is established on the site adjacent to the Futaba Factory. Headquarters functions are transferred in order to implement newest machine equipment and integrate production and sales


Headquarters relocated from Midorigaoka, Kofu City, Yamanashi Prefecture to current location of Kai City, Yamanashi Prefecture


Listed on JASDAQ


Eiji Fukasawa appointed as the company's second President and Nobuo Fukasawa (its first President) is appointed Chariman, with the aim of strengthening management foundations and developing sales strategies for the future


Company name changed to Kohsai Co., Ltd. in celebration of its 50th anniversary


Kohsai launches new businesses as it celebrates its 80th birthday,


Kohsai launches new businesses as it celebrates its centennial,
making itself a new market leader.

The Future We Build