Koshu hand-carved seals

Koshu hand-carved seals Koshu tebori insho

One-of-a-kind signature seals
Elaborate creation by skilled artisans


What is Koshu hand-carved seals ?

Koshu Tebori Insho are hand-engraved personal signature stamps produced in Kofu City and Fujiyoshida City of Yamanashi Prefecture. Bringing together all of Yamanashi’s engravers, dealers, and material producers, this local industry is unlike those found in any other prefecture. One of the special characteristics of Koshu Tebori Insho seals is that the materials are specified to Japanese boxwood, water buffalo horn, and crystal. The crystal seals were developed using the crystal cutting and polishing technologies unique to the Koshu region. Seals made of boxwood or water buffalo horn are made using a carving knife called kiteito to roughly carve the part of the seal for the characters in the owner’s name, followed by a finer carving using a different carving knife called hansashito to finish the lettering. For a crystal seal, the face is carved out by tapping a round chisel blade with a small mallet, and a flat chisel is used to complete the lettering through the same process. The face of the seal is smoothed with a whetstone, and the letters appear written as mirrored within this space. Passing down the traditional tools and techniques is an important part of the Koshu seal-making process. The production of the engraving knives is also an inherited practice that is necessary for the full expression of a beautiful completed seal impression.


The history of Yamanashi’s Koshu Tebori Insho began with the discovery of massive, high-quality crystals from the Ontake mountain range. In 1837, a crystal-processing factory was established in the Ontake area located in the suburbs of Kofu. Several different processing technologies emerged, and the number of crystal artisans and manufacturers increased. Woodblock carving techniques progressed, and boxwood and water buffalo horn as well as crystal started to be used as materials. The development of the signature seal industry can be seen in documents such as the 1854 Koshu Consumers’ Guide. These documents mentioned woodblock artists working in the printing industry in Kofu City, while in other publications, orders for materials such as rare grass-infused crystal and water buffalo horn seal materials were noted. The documents suggest that at this time there were already skilled artisans in business with various kinds of materials in circulation. The demand for signature stamps from the general public increased dramatically with the Grand Council of State Proclamation in 1873, and the market expanded through travelling and mail-order sales unique to Yamanashi Prefecture.

General Production Process

  1. 1. Surface polishing The custom of stamping important documents with hanko seals dates back to the Edo Period, when it became a practice among peasants and other common people. It was from this time that seals were registered in official booklets, with each person possessing an individual seal. Hanko seals were used to protect important assets, and played a vital role as a form of personal identification. Just as each person is unique, seals became valued as one-of-a-kind personal items. The major processes in making Koshu Tebori Insho vary considerably depending on even slight differences in the seal materials. Created by expertly skilled artisans, the impression of a Koshu hand-engraved seal each has its own unique style. The first step in the seal-making process, surface polishing, involves leveling out the face of boxwood, water buffalo horn, or crystal seal on a whetstone.
  2. 2. Lettering The lettering process is designing the arrangement of letters, graphing them out, and then writing their mirror image on the face of the seal. For a proper seal, an artisan must perform the lettering process by hand so that no two names appear the same way when carved, which also enhances the security of the seal. There are several types of traditional seal fonts, including shoten (small seal script), inten (ancient seal script), insoutai (seal script), reisho (clerical script), kointai (rounded clerical script), kaisho (block script), gyousho (semi-cursive script), and sousho (cursive script). Shoten originated as a public script when written characters were standardized during China’s State Unification under the Emperor Qin Shi Huang. The elegant style of shoten is considered suitable for registered seals and bank seals for women. Based on shoten (small script), inten (ancient seal script) is the style most often used on seals. It was used as the emblem of bureaucrats in ancient China, and in modern times, is commonly seen on registered seals. Inten has an aura of authority. Insoutai (seal script) is a font special to seals. Derived from inten, it is designed so that the lettering touches the edges of the circle frame. Developed during the Qin Dynasty of ancient China, reisho (clerical script) was made by simply straightening the lines of the shoten script. The kointai (rounded clerical script) was invented in Japan based on reisho, and has been used to create national seals, shrine seals, and private seals since antiquity. It is also called Yamato Intai (ancient Japanese script), and reflects the individuality and special traits of the artisan. Kaisho (block script) is a basic and familiar writing style used when learning Chinese characters. Gyousho (semi-cursive script) is a half-cursive form of basic scripts. It is not as curvy as the sousho full-cursive writing, but exists stylistically between sousho and kaisho block lettering. It is favored among women for the beauty and softness of its lines. Sousho (cursive) is a flowing script written with fluidity.
  3. 3. Engraving (Boxwood or water buffalo horn) The part of the seal around the lettering is roughly carved out with a carving knife called kiteito. The engraving of the lettering is completed with the fine hansashito carving knife. Either the press-carving method in which the artisan applies pressure while carving, or the pull-carving method, in which the shape of the engraving is pulled out is used to finish the carving.
  4. 4. Engraving (Crystal) The side of the seal opposite from the face is painted with black ink so that the lettering on the face is easier to see. The artisan uses a round bladed chisel and small mallet to chisel out the surface. The lettering is finished using a flat blade chisel. Finally, the carved surface is cleaned up in a similar fashion using another special chisel blade used to carve deeply and to clear out left over material.

Where to Buy & More Information

Kaiterasu (Yamanashi Jibasangyo Center)

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