What is sayagaki — The history and how to read the appraisal information inscribed on shirasaya

What is sayagaki

On the shirasaya used to store nihontō, characters are often written in ink on the flat surface of the saya. This is called sayagaki. Distinct from the mei on the nakago engraved into the blade itself, it is a practice in which the tōkō's name, the nagasa, the appraiser's signature, and similar information are recorded on the outside of the shirasaya, and it has served the role of conveying a sword's provenance and appraisal information to later generations. For nihontō, which are often handled while kept in their saya, the information written on the surface of the saya is also an important clue for gauging the contents without drawing the blade. When handling nihontō at sword dealers or museums, removing the shirasaya and checking for the presence and content of sayagaki has become one of the basic steps in practical appraisal work.

The origins of sayagaki — a practice born from the organization of daimyo sword collections

The origins of sayagaki are said to lie in the practice of daimyo households, which held large collections of swords, writing the tōkō's name and nagasa on the saya in order to organize information about the swords stored in their storehouses. The stored sword collections of samurai households often numbered in the tens to hundreds, and it was difficult to distinguish the contents from the shirasaya alone. By recording information on the surface of the saya, the management of stored swords became significantly easier. It is thought that this practical measure gradually came to carry an appraisal significance of "certifying authenticity" over time. What was originally a practical memorandum for inventory management changed in character into a document substantiating the value of the sword itself, through the hands of authoritative appraisers.

The role played by the Hon'ami family and appraisers

Indispensable to any account of the history of sayagaki is the Hon'ami family, which has long made the appraisal of nihontō its hereditary profession. Sayagaki produced by Hon'ami family appraisers such as Hon'ami Chōshiki, Hon'ami Shinzen, and Hon'ami Ringa remain on numerous swords to this day. The Hon'ami family appraised swords at the request of the shogunal house and various daimyo, and was charged with the duty of returning the results to the sword's owner in the form of a kanteisho called origami, or in the form of sayagaki. When sayagaki was affixed to a sword appraised by the Hon'ami family, a system was established in which the authoritative view on the sword's maker and period was made visible. Today, not only the Hon'ami family but also members of sword preservation societies and specialists well-versed in swords may produce sayagaki, and who wrote it has become one of the factors that determines the value of a sayagaki.

The information recorded in sayagaki and how to read it

The content written in sayagaki varies depending on the writer and the period, but the typical entries are as follows.

• Tōkō name——the name of the tōkō presumed to be the maker
• Nagasa (dimensions)——the length of the blade expressed in shaku and sun
• The appraiser's signature and kaō——the signature indicating who appraised and recorded it
• Date of inscription——the period when the sayagaki was made
• Supplementary notes on origin and provenance——some examples include detailed accounts of former owners and the circumstances of transmission

Not all entries are necessarily present, and many sayagaki are simple, listing only the tōkō name and the appraiser's name. On the other hand, some sayagaki contain detailed accounts of the blade's notable features and the history of its transmission, and in such cases they hold value as a kind of short appraisal essay. The style of the writing, the language used, and the very format of writing directly on wood in ink rather than on paper can sometimes allow one to estimate the approximate period of inscription. However, one should note that sayagaki are often written in a highly skilled, cursive script, making them difficult to decipher without specialized training in reading such styles.

The relationship with kanteisho — differences in the role each fulfills

In the modern sword trade, the kanteisho issued by official appraisal organizations such as the NBTHK (Society for the Preservation of Japanese Art Swords) has become the primary reference for judging the authenticity and period of a sword. Sayagaki differs from such official kanteisho both in its circumstances of origin and in its character. While a kanteisho is a document issued by an organization conducting examination under unified standards, sayagaki is written by a specific individual appraiser based on their own knowledge and judgment, and is close to what one might call a personal signed opinion. The two may sometimes be contradictory and sometimes mutually reinforcing, and one is expected to approach understanding a sword's background by comparing both, without treating either one as absolute. A sword with an old sayagaki still intact is also evidence that it has been carefully passed down over a long period, and holds value as a document that tells the story of its provenance.

The significance of sayagaki today and points to note

Sayagaki is, after all, information recorded on the shirasaya, which is an accessory, and is not the mei itself struck on the blade. It is therefore essential to compare the content of the sayagaki with the mei cut into the nakago of the blade and the content of the kanteisho issued by official appraisal organizations, and to arrive at a comprehensive judgment. When a shirasaya deteriorates with age, it may be remade anew, and in that process it is possible for the sayagaki alone to convey old information while the current shirasaya itself is new. There is also a practice of transcribing the wording of the sayagaki written on the old saya onto the new saya when the saya is replaced, and in such cases it is desirable to confirm, among other things, who copied it and when. Understanding the historical weight that sayagaki carries, and then approaching it as one piece of reference information to be read in conjunction with kanteisho and the mei on the nakago, is an important perspective when engaging with nihontō.