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Home > Passions of Artisans #019 Joetsu Crystal Glass Co., Ltd.

#019 Joetsu Crystal Glass Co., Ltd.2015/01/15

Continuing to challenge new possibilities with colorful glass products

Long-established glassmaker with a history
of more than 100 years

The company was founded in 1905. Joetsu Crystal Glass Co., Ltd., creator of Japan’s first thermometer, boasts a diverse track record as a long-established player in the glass industry. This includes producing glass walls for the New Imperial Palace and the Imperial Hotel, reproducing azure-colored glass beads for Chuzonji Temple, glass for the Shosoin treasure house, and chandelier glass for the Akasaka State Guest House, and providing glass trophies for sumo tournament winners.

The company’s Head Office and Tsukiyono Glassworks are located in the district of Tsukiyono, Minakami-cho, Tone County, Gumma Prefecture, in a beautiful natural setting within view of the Tanigawa mountain range. When the company was first established, the factory was in Tokyo. But after the war, shortages of fuel and coal made it more economical to move to the current site, where lignite was easier to obtain.

Currently, the company’s sales profile consists of 60% OEM and 40% direct sales. “We have a broad involvement in OEM sales, including commemorative pieces for the Japanese Red Cross Society, as well as bridal gifts and others. In future, we would also like to increase our direct trade with retailers,” says the company’s President and CEO, Yoshihiro Kurata.

Later, the focus shifted from making glass for thermometers and other scientific purposes, to lampshades, vases, tableware and other glass products used in everyday life. Yoshihiro Kurata, the company’s 3rd president, has continued to challenge new possibilities for glass in collaboration with famous artists and designers.

The spirit of challenging the possibilities of glass

The glass wall in the 1st floor lobby of the Imperial Hotel is the work of sculptor Minami Tada. This gigantic artwork is 8 meters high, 25 meters wide and contains more than 8,000 glass blocks! The technical prowess needed to express the precision and subtle color differences required by artists is typical of this company.


In 1990, the company opened “Tsukiyono Vidro Park”, a glassmaking theme park that includes tours of a glass workshop and hands-on experience of glass-blowing, as well as a glass art museum exhibiting glass products from around the world. The facility attracts as many as 400,000 visitors every year.

“We are particularly proud to have produced so many excellent craftsmen. We often joke that if our glassmakers were told that something was impossible, they would immediately reply, ‘No, we can do it!’. This spirit of endeavoring to meet any request has helped us to develop new technologies, and has even resulted in awards and commendations for our craftsmen.”

Among the many decorations conferred on the company’s glassmakers, one of them has been awarded the 6th Order of the Sacred Treasure and three the Yellow Ribbon Medal. Factories where craftsmen receive such honors are rare anywhere in Japan; this feat has even prompted official visits by the then Crown Prince Akihito (now the Emperor) and Crown Princess Michiko, as well as the current Crown Prince Naruhito. These are all ample proof of the company’s outstanding technical prowess.

Around a glass-melting furnace operating at a temperature of 1,500 degrees centigrade, glassmakers lovingly create each piece by hand. The various techniques they use include the free-blowing method, in which the glassblower spools molten glass onto a blowpipe, then blows into the pipe while shaping the piece; the mold-blowing method, in which molten glass is blown into a mold; and the stretching method, in which soft glass is stretched by the force of gravity while it is being shaped. These various methods are used to best effect in creating a number of pieces at the same time.

Each of the company’s products is individually crafted by hand. Inside the factory, glassmakers can be seen working at a crucible-type melting furnace at a temperature of 1,500 degrees centigrade. From this, they extract quantities of red-hot molten glass resembling a thick syrup, then shape it into glassware, watching intently all the while.

“For larger pieces, five or six glassmakers will form a team to shape the molten glass quickly before the temperature starts to fall, then piece the glass together with impeccable timing. The individual skills and teamwork of our craftsmen that make this possible are the strengths of our company.”

A particular feature of this company is its variety of complex and unique techniques, such as the lace glass method, which seems to interweave strands of glass together, and the patented method of forming glass in drape formation. Even processes such as polishing, which are generally regarded as separate trades in the glassmaking industry, are all done in-house.

Beautiful colored glass produced by trial and error

Another attraction of the company’s products is the richness of their color. For example, its “birthstone glass” comes in twelve colors, representing the various birthstones from January to December. This multiplicity of color and the subtlety of coloring, reminiscent of gemstones, is something that cannot be emulated by other companies.

Colored glass is formed by a chemical reaction when mixing copper, cobalt and other metals with clear glass. If more than one color is used at a time, the expansion coefficient increases and the glass becomes more fragile, while problems such as turbidity and air bubbles can also occur. Production methods are therefore required to achieve good coloring while eliminating bubbles. And because this is more costly, time-consuming and labor intensive, other glass factories tend to focus on just a few colors.


A characteristic of the company is that it makes products based on free thinking. When the company opened a restaurant serving locally brewed beer 15 years ago, it developed the “mountain sunset” glass specifically for beer. This was based on the idea that, when beer was poured into the glass, the inside of the glass would look like a sky at sunset. It is now an established Father’s Day gift.


The beautiful curves of the “birthstone glasses”. The company has chosen colors to represent birthstones from nearly fifty different possibilities.

“But in our case, the number of colors gradually increased as we responded to different requests, and before we knew it, we had more than 60 types, including dark and light shades. Many of these are produced by trial and error. For example, “Shosoin sepia” resulted from an effort to restore glassware in the treasures of Shosoin.”

Hiroki Kurata, in the 4th generation of the founding family, is Deputy Manager of the Administration Department. “We would like to become a general consultant on glass,” he says, revealing an attitude of positively accepting original creation.

“Tsukiyono Artists’ Club is an opportunity for future challenges by young glassmakers at Tsukiyono Glassworks. It also functions as a test case for the market, in the broad sense. Some of the works presented here have gone on to be commercialized and established in the market,” says Hiroki Kurata.

“For a few years now, artists and creators in fields where we previously had no connection have started to take an interest in glass, as a ‘material for artistic expression’. Specialists in flower arrangement or tea ceremony, for example, use glass when making their own tools, while others use it for spatial design or creation, tableware, interiors and so on. As a company, we have always liked making new challenges. We see our responsiveness, technical capability, production capability and track record as a kind of product. Our wish is create a new manufacturing style, based on solutions to make wishes come true.”

Developing new techniques through “creative glassmaking activity”

The company is promoting “creative glassmaking activity” as part of its business content. The “Tsukiyono Artists’ Club” is a group of five young glassmakers who are continuing the techniques of glass coloring, mold blowing and lace glass. Last year, a touring exhibition of works produced in each of their names was held in “Madu” houseware stores.

A section of the “Young Glassmakers’ Touring Exhibition” held in 9 Madu stores nationwide from March to August 2013. The exhibition featured a range of works reflecting the artistic sense of young glassmakers, differing from the tone of pieces produced by Tsukiyono Glassworks hitherto.
(Photo source: Madu)

“By encouraging our craftsmen to our stretch the bounds of conventional techniques and challenge new ones, we hope that products with a connection to the future will emerge. Ever since we were founded as a factory producing glass for scientific uses, we have produced a really large variety of products in tune with changes in the times. It is the glassmakers in each age who have made this possible. We will invest energy in nurturing craftsmen who will inherit the technology of their forebears and pass it on intact to those of the future,” says Hiroki Kurata.

President Yoshihiro Kurata hopes to build on this idea. “I would like to create products on the next level up, using techniques only known by our company, such as layering colored glass to show beautiful gradations,” he explains.

“What we are attempting now are amazing new products that will even make people with knowledge of glassmaking techniques wonder how on earth they were made! And we hope Rin crossing will support our sales route development not only in Japan but overseas as well.”

“Government support schemes sometimes end after one year or a single installment, and this can be frustrating,” adds Hiroki Kurata. “As such, the longer term approach of SME Support Japan’s ‘Rin’ project to assist sales route development is greatly appreciated. I hope Rin crossing will continue as a project that provides solid support for our sales route development. And in future, we want to make a positive attempt at collaborating with other sectors.”

Joetsu Crystal Glass Co., Ltd.

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