Inside the NBTHK Shinsa Committee: How Reviewers Are Selected, How Meetings Run, and How Sword Grades Are Determined

NBTHK — The Central Authority in Japanese Sword Authentication

The "Japan Art Sword Preservation Society (NBTHK, Nihon Bijutsu Touken Hozon Kyoukai)" is a public-interest incorporated foundation dedicated to the preservation, research, and promotion of Japanese swords. Established in 1948. It is widely recognized as the most authoritative authentication body in the sword industry, and the "authentication certificates" issued by NBTHK serve as proof of sword value in both domestic and international markets.

However, few people have a detailed understanding of how NBTHK examines swords and determines their grades — the internal processes involved. This article explains the workings of shinsa (authentication) from a practical industry perspective.

NBTHK Authentication Grades — Four Types of Certificates

NBTHK issues authentication certificates in the following four grades (listed in order of highest ranking):

Tokubetsu Juyo Token (Specially Important Sword) The highest rank. Exceptionally excellent works among past important swords. Examination is held once per year (special examination session). The number of designations is strictly limited, typically several dozen per year.

Juyo Token (Important Sword) Particularly valuable works among preserved swords. Examined at 1-2 examination sessions per year. Receives the highest evaluation as "juyo-attached" in domestic and international auctions.

Tokubetsu Hozon Token (Specially Preserved Sword) Premium swords where condition and authenticity have been verified. Can be upgraded from hozon token status through petition.

Hozon Token (Preserved Sword) Swords where authenticity has been confirmed and preservation condition meets a certain standard. This is the entry-level grade for NBTHK.

Selection of Authentication Examiners

The "shinsa iinkai" (authentication examiners) who conduct NBTHK's examinations are selected based on the following criteria.

Selection Criteria

Track Record in Sword Authentication: Experts with long-standing experience in sword research and authentication. Candidates are primarily drawn from appraizers in the Honami family lineage, sword researchers, and veteran sword merchants.

Specialization in School Knowledge: The committee is composed of experts versed in specific periods, regions, and schools. For example, specialists in the Bizen tradition, Soshu tradition, and Yamato tradition are needed, with committee members capable of handling each school.

Continuous Relationship with NBTHK: A prerequisite is a long-standing trust relationship with the organization. Authentication examiners are often appointed confidentially, and external recruitment is not conducted.

Examiner Terms and Changes

Authentication examiners have no fixed terms and often serve for many years. When examiners retire due to age or health reasons, replacement examiners are appointed. NBTHK's policy is not to fully publicize examiner names, making this tacit knowledge within the industry.

Format of Authentication Sessions

Advance Application and Acceptance

Sword owners wishing to have their swords authenticated submit application documents (copies of registration certificates and basic sword information) and examination fees to NBTHK. Examination fees vary by grade and sword type (typically several thousand to tens of thousands of yen for preservation examination, and higher for important sword examination).

After application, the sword is presented at a designated location and time (or sent by mail).

Flow on Examination Day

Medooshi (Individual Viewing): Examiners take turns holding and appreciating the sword. This "medooshi" is the core of the examination. Examiners first regard the sword as mumeizai (unsigned; creator unknown) and independently judge its creator, period, and school based on characteristics of the hamon, jihada, general form, and nakago.

Opinion Formation: After each examiner individually views the sword, they form their opinions. At this stage, discussion among examiners is kept to a minimum (to prevent preconceptions and bias from peer influence).

Opinion Comparison and Discussion: After all examiners complete their medooshi, opinions are compared. If opinions align, conclusions are reached promptly. If opinions differ, discussion takes place and conclusions are reached through voting or consensus.

Verification Against Signature: The sword's mei (the maker's name inscribed on the nakago) is confirmed, and consistency is checked between the "estimated creator, period, and school" that examiners independently determined. Even for signed swords, the authenticity of the signature (true signature, later signature, covered signature, etc.) is examined.

Grade Determination: Based on examination results, the committee decides whether to approve, deny, or downgrade the applied grade (such as denial of preservation application).

Certification Standards by Grade

Certification Standards for Hozon Token (Preserved Sword)

• Authenticity: The sword must be genuine (authentic work)
• Condition: The polishing condition meets a certain standard (no severe rust or defects)
• Consistency with Registration Certificate: The basic information recorded on the registration certificate matches the actual sword

Many swords can be certified as hozon token. However, swords in poor condition or judged to be counterfeit are denied.

Certification Standards for Juyo Token (Important Sword)

Examination from hozon token to juyo token status requires meeting the following criteria:

• Excellence of Deki (Workmanship): All elements — hamon, jihada, and general form — must be at an exceptionally high level even for that particular sword smith, period, and school
• Good Condition: Absence of major damage, rust, or excessive polishing wear
• Academic Value: The sword possesses characteristics of reference value for sword history and school research

When certified as a juyo token, the sword is listed in the "Juyo Token Illustrated Catalog."

Certification Standards for Tokubetsu Juyo Token (Specially Important Sword)

Works among important swords judged to possess value equivalent to national treasures or important cultural properties. The standards are extremely strict and must satisfy all of the following:

• Provenance and history are clearly documented
• The sword is widely recognized within the industry as a representative work of that particular sword smith
• Condition is exceptional (minimal wear, damage, or rust)
• Value has been discussed in prior examinations and research papers

Issuance and Use of Authentication Results

Once examination is complete, NBTHK issues an "authentication certificate (authentication card)" for the sword. The certificate includes:

• Certification grade (tokubetsu-juyo, juyo, tokubetsu-hozon, hozon)
• Estimated creator (sword smith name, school, origin)
• Estimated period
• Basic sword measurements (blade length, curvature, width at base, width at point, etc.)
• Year of examination (in Japanese calendar)

Use in the Market: Swords with NBTHK authentication certificates are treated as "guaranteed" in domestic and international auctions and at sword merchant shops. Higher grades command price premiums.

Possibility of Reapplication: Even denied swords may be reapplied for after condition improvements such as repolishing.

Limitations of Authentication and Industry Discussion

The industry recognizes that NBTHK's authentication is not infallible.

Examiner Subjectivity: Sword authentication is not objective science but depends on examiners' experience and visual acuity. Evaluations may change over time (instances where swords once certified as important were later disputed, etc.).

Review Mechanism: NBTHK has an internal system for reviewing certifications, but reviews are not conducted frequently.

Comparison with Foreign Institutions: Evaluations from foreign authentication bodies (such as Honami International) sometimes differ, occasionally resulting in divided market assessments.

Conclusion — NBTHK Authentication as the Crystallization of "Comprehensive Connoisseurship"

NBTHK's sword authentication is conducted through "collective knowledge" combining the connoisseurship of experts with years of experience. The process of individual examiner eyes independently viewing the sword, followed by comparison and discussion of opinions, is a rational system designed to minimize personal bias.

The authentication certificate should be understood not as "complete objective proof" but as "the judgment rendered at present by an authoritative group of industry experts." Nevertheless, the authority and market influence of NBTHK authentication certificates remain unparalleled in the contemporary Japanese sword industry.