Koshu Seals

Mention is made in a late Edo period (1600-1868) ""shopping guide"" for Kofu, the capital of Yamanashi prefecture, that seals were being sold and skilled craftsmen were making blocks and seals in wood.
In another document dating from the same period, there is an order for a rather rare kind of quartz containing grass and for water buffalo horn from which to make seals. This would seem to prove that already during the second half of the 19th century, all manner of seals were being produced in Kofu.

The shear degree of development of the carving skills, the preparation of materials for making seals including the polishing of quartz as well as the use of boxwood and horn, has reached a level of organization that can not be found in any other prefecture in Japan. All the specialists including the carvers and seal marketing specialists can be found at work in Yamanashi prefecture and the situation is the same today as it has always been.

Yamanashi