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 refers to hand-engraved personal signature stamps produced in the Yamanashi Prefecture cities of Kofu and Fujiyoshida. Bringing together all of Yamanashi’s engravers, dealers, and material producers, this local industry is unlike that found in any other prefecture.
One of the special characteristics of Koshu Tebori Insho seals is the designation of their materials as tsuge (box tree) wood, water buffalo horn, or crystal. The crystal seals were developed through crystal-cutting technology unique to the Koshu region.
If the seal is made of tsuge wood or water buffalo horn, the artisan uses a kiteito blade to roughly carve the part of the seal for the characters in the owner’s name, with a finer hansashito blade applied to finish the lettering. For a crystal seal, the face is carved out by tapping a curved chisel blade before a blunt-bladed chisel completes the lettering through the same process. The face of the seal is smoothed with a whetstone, and the letters appear written as mirrored (reverse) images 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 allows for the full expression of a beautiful completed seal impression.


The history of Yamanashi’s Koshu Tebori Insho began with the exhumation of massive, high-quality crystals from the Ontake mountain range. In 1837, a crystal-processing factory was established in the Ontake area outside of Kofu. Several different processing technologies emerged, and the number of crystal artisans and dealers increased. Woodblock carving techniques progressed, and tsuge wood and water buffalo horn as well as crystal came into use as seal-making materials. The development of the signature seal industry can be seen in documents such as the 1854 Koshu Consumers’ Guide. These writings mentioned woodblock artists working in printing in Kofu City, while other publications ran orders for materials such the rare grass-infused crystal Gokujou Gusaire Rokkaku (“highest-quality hexagon with grass”) and water buffalo horn seal materials. The documents suggest that at this time there were already skilled artisans in business, with various kinds of seal materials in circulation.
The demand for signature stamps from the general public increased dramatically with the Grand Council of State Proclamation of 1873, and the market expanded through the travelling and mail-order sales special to Yamanashi Prefecture.

General Production Process

  1. 1. Inmensuri (Surface polishing) The custom of stamping important documents with hanko seals dates 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 used to protect important assets 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. Inmensuri (surface polishing), the first step in the seal-making process, involves leveling out the face of a tsuge wood, water buffalo horn, or crystal seal on a whetstone.
  2. 2. Ji-ire (Lettering) The ji-ire (lettering) process entails designing the arrangement of letters (inkou), graphing them out (jiwari), and then writing their mirror image on the face of the seal. For a proper seal, an artisan must perform the ji-ire 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 Qin Emperor. The elegant style of shoten is considered suitable for official stamps such as women’s registered seals and bank seals.
    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 official seals. Inten boasts an authoritative air.
    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.
    Developed during the Qin Dynasty of ancient China, reisho (clerical script) simply straightens 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. Also called Yamato Intai (ancient Japanese script), it 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 (Tsuge wood or water buffalo horn) The part of the seal where the lettering will go is roughly carved out with the kiteito blade. The engraving of the lettering is completed with the fine hansashito blade, either through 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 as the artisan carves.
  4. 4. Engraving (Crystal) The side of the seal opposite the face is painted with black ink so that the lettering on the face is easier to see. The artisan uses a curved steel blade to chisel out the surface before the lettering is chiseled with a blunt steel blade. The indented surface is cleaned up in a similar fashion with a steel chisel blade used carve deeply and clear out left over material.

Where to Buy & More Information

Kaiterasu (Yamanashi Jibasangyo Center)

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