Understanding NBTHK Certification — How to Read Papers and Grade Differences

NBTHK (Japan Art Sword Preservation Society)

The most authoritative organization for certifying the authenticity and quality of Japanese swords is the public interest incorporated foundation Japan Art Sword Preservation Society (NBTHK). Formally established on February 24, 1948 (Showa 23), this organization's mission is the preservation, research, and promotion of Japanese swords. Today it functions as a globally recognized authentication body, and the certification documents (examination certificates) issued by NBTHK are treated as the most trusted certificates of authenticity in international sword transactions.

Every year, the society examines thousands of swords brought from both domestic and international sources and assigns grades based on strict criteria. It also contributes broadly to the transmission of sword culture through publishing research works, holding exhibitions, and supporting the training of young sword smiths.

The Four Authentication Grades — From Preservation to Specially Important

NBTHK certification documents have four grades. The color of the certificate differs by grade, making it immediately recognizable just by looking at the physical document.

Preservation Sword (Hozon / Yellow Certificate)

This is the entry-level grade given to swords judged to be "worthy of preservation." It mainly includes swords from the Edo period onward, and the prerequisite for certification is that the hamon is clearly visible, the jihada shows no serious damage or rust, and the overall form and construction are well-balanced.

This is the grade that collectors first seek to obtain, and it has the largest market circulation. While the price varies depending on the type of sword, blade length, and quality, it is entirely possible to find quality examples in the Hozon class in the range of 500,000 to 1.5 million yen.

Specially Preserved Sword (Tokubetsu Hozon / Blue Certificate)

This is a higher grade obtained when exceptionally well-made swords among Hozon weapons pass a promotion examination. It is necessary to demonstrate outstanding quality in terms of the sharpness and brightness of the hamon, the density of the jihada, and the overall harmony of the form, and the pass rate of the examination is not high.

It includes ko-katana from before the Muromachi and Momoyama periods, and this grade is valued for the timeless quality and universality of its craftsmanship. Its market value significantly exceeds Hozon swords, and many advanced collectors recommend Tokubetsu Hozon or higher as the minimum standard when selecting a sword to serve as the axis of a serious collection.

Important Sword (Juyo Token / Red Certificate)

This is a prestigious grade recognized at an annual examination. In consensus-based reviews by multiple specialist committee members, in addition to the exceptional quality of the sword itself, historical significance, clarity of provenance (history), and stylistic typicality of the period of manufacture are important evaluation criteria.

The majority consist of masterpieces by renowned smiths from the Kamakura, Northern and Southern Courts, and Muromachi periods, or outstanding works representative of the Edo period, and they receive high evaluation at international auctions. Although difficult to obtain and expensive, Juyo Token class represents a worthy goal for collectors seeking both completeness in their collection and the stability of future asset value.

Specially Important Sword (Tokubetsu Juyo Token)

This is the highest grade designation given by NBTHK. It is a ranking second only to National Treasures and Important Cultural Properties, and is recognized worldwide as a certification indicating the true pinnacle among existing Japanese swords. The number of swords so designated is extremely small, and circulation on the market is virtually non-existent.

Swords with provenance from imperial or shogunal families, masterworks that serve as benchmark works for sword research, and outstanding examples recognized as landmarks in sword history fall into this grade. Simply owning such a sword represents the highest status as an international collector.

The Examination Process — From Application to Certificate Receipt

To undergo NBTHK examination (authentication), the following process must be followed.

1. Application and Registration

Hozon and Tokubetsu Hozon examinations are held twice yearly (spring and autumn), while Juyo Token examinations are held once per year. The application period is announced approximately 2-3 months before the examination, and can be confirmed on the society's website and member notifications. At the time of application, a submission form containing basic information such as the blade length, signature (mei), and registration certificate number must be filed.

2. Submission and Examination Day

On the day of the examination, the sword is brought to the designated venue (with the Tokyo Sword Museum serving as the main location). An examination number is assigned at registration, and the sword is delivered to the examiners. The examination involves multiple specialist committee members handling each sword and making comprehensive assessments of the hamon, jihada, form, signature (mei), damage, rust, and polishing condition. The applicant does not attend the examination itself; only the sword is examined.

3. Result Notification and Certificate Issuance

Examination results are notified by document several weeks later. If certified, a certificate (examination certificate) is issued and returned with the sword. There are cases of non-certification, in which case only a "failed" notification is provided without detailed explanation of reasons.

4. Promotion Examination (Hozon to Tokubetsu Hozon, etc.)

For those wishing to upgrade a sword with a lower-grade certificate to a higher grade, a "promotion examination" can be applied for. It is accepted at every examination session, and the examination fee is the same as for new applications.

How to Read an Authentication Certificate — What to Look For

NBTHK authentication certificates contain the following information.

• Type: Sword type such as katana, wakizashi, tanto, spear, or naginata
• Signature (mei): The name of the sword smith (often "unsigned")
• Period: Estimated period of manufacture (Kamakura, Muromachi, Edo, etc.)
• Province (Region of Origin): Manufacturing location (Bizen, Soshu, Yamashiro, etc.)
• Blade Length (hachō) and Curve (sori): Measurements in centimeters
• Characteristics of the Hamon: Description of the type of random blade pattern, condition of boiling, and degree of nioi
• Characteristics of the Jihada: Type of surface pattern and presence or absence of reflections
• Category (Grade): Hozon / Tokubetsu Hozon / Juyo Token / Tokubetsu Juyo Token

The grade can be immediately determined by checking the color of the certificate (yellow = Hozon, blue = Tokubetsu Hozon, red = Juyo Token). Additionally, the certificate bears a unique examination number, which can be verified with the society to confirm authenticity.

Frequently Asked Questions (FAQ)

Q: Can I sell a sword without obtaining NBTHK certification?

A: There are no legal issues with doing so, but swords without certification documents typically command significantly lower purchase prices. Especially for first-time purchases or if you anticipate future sales, it is strongly recommended to select swords with certification documents.

Q: Which is superior, Hon'ami authentication or NBTHK authentication?

A: Hon'ami family authentication is a traditional family lineage authentication that has continued since the Edo period and carries high authority, particularly in matters of provenance certification. NBTHK employs a public committee review format with high transparency and is widely recognized as an international standard certificate. Neither is "superior" to the other; a sword bearing both certificates demonstrates particularly high credibility.

Q: Can NBTHK authentication be obtained for Japanese swords purchased overseas?

A: Yes, it is possible. However, when bringing a sword into Japan, import procedures and registration under the Swords and Firearms Control Law are required. Since the procedures are complex, it is recommended to consult with specialist sword dealers or import-export agents.

Q: Does a certification document guarantee authenticity?

A: NBTHK certification documents provide highly reliable proof of authenticity, though the certificates themselves are occasionally forged. When purchasing, develop the habit of verifying the certificate's unique number by contacting NBTHK directly. Additionally, the paper quality, printing, and condition of the official seals on the certificate can serve as references in assessing authenticity.

Q: What is the examination fee?

A: As of 2025-2026, examination fees vary depending on sword type and blade length. For details, please check the official NBTHK website (nbthk.or.jp).

Certification Documents Are the Foundation of a Collection

Selecting swords with authentication certificates is the foundation of Japanese sword collecting. Beyond guaranteeing authenticity, the presence or absence of a certification document makes a decisive difference in future sales, insurance valuations, and asset verification during inheritance. TOUKENZA lists only swords with authentication certificates, so you can browse our catalog with confidence. Utilize our grade-specific filtering features to find a sword that matches your budget and target grade.