NBTHK papers

NBTHK and NTHK: two acronyms that are not worth the same

The NBTHK — Nihon Bijutsu Tōken Hozon Kyōkai (日本美術刀剣保存協会), the society for the preservation of the Japanese sword as art — was founded in 1948, publishes the journal Tōken Bijutsu and runs the Japanese Sword Museum at Yokoami, in the Sumida ward of Tokyo. Its examinations, the shinsa, and its published criteria are the reference of the international market.

The NTHK — Nihon Tōken Hozonkai (日本刀剣保存会) — claims an older tradition, going back to 1910. After a split, there are now two separate organisations that do not issue the same thing. The NTHK-NPO, registered as a non-profit in 2002, examines once a month and issues kanteisho (鑑定書), shinteisho (審定書) — when the signature is good but the condition of the blade does not allow a kanteisho — and, for outstanding works, a yūshūtō kanteisho (優秀刀鑑定書). The full 60-to-100 point scale, with the highest grades, belongs to the other branch, the one that holds examinations abroad, above all in the United States:

All three systems are serious, but they are neither equivalent nor interchangeable: a paper from either NTHK is not a Hozon and does not turn into one, and the same word, such as shinteisho, does not mean the same in each.

The NTHK grew out of a magazine: in 1910 Takase Ukō (高瀬羽皐, 1853–1924) founded Tōken to rekishi (刀剣と歴史, Swords and History), which the society still publishes. Its paper is also unlike the NBTHK’s: on the inside it describes the blade field by field — the signature (meibun), the forging (kitae), the hamon, the bōshi, the carvings (chōkoku), the tang (nakago) and remarks (bikō) giving the province and the estimated period, such as “around Ōei” — and it carries the oshigata of the tang with its seal. The NBTHK’s kanteisho and shiteisho do not describe the blade; only the Jūyō comes with a reasoned text, the setsumei.

Both branches keep the same name, Nihon Tōken Hozonkai (日本刀剣保存会), and a journal of the same title, Tōken to rekishi, so the name alone is not enough. Going by what each publishes on its website, they can be told apart as follows. The NTHK-NPO, a non-profit body (特定非営利活動法人, tokutei hieiri katsudō hōjin), has its office in Shinagawa (Tokyo) and holds its examinations on the third Sunday of every month except August (hozonkai.jp). The other has its headquarters in Kanda, in Chiyoda ward (Tokyo), and its office in Osaka; it examines at headquarters on the second Sunday of every month and has also examined in San Francisco with the Northern California sword club (nihontouken.org). This second society tells its origin like this: the journal first appeared in the spring of 1910 and the society was founded in October 1912. Faced with a paper from either of them, what identifies the issuer is the seal and the address it carries, not the acronym.

The four NBTHK levels

The order is compulsory and cumulative: only an item that already holds Hozon may be submitted for Tokubetsu Hozon; only one that passed Tokubetsu Hozon may go to Jūyō and only one that passed Jūyō may go to Tokubetsu Jūyō. No step is skipped, and the calendar sets its own pace: a blade cannot go from nothing to Jūyō in a single year. In practice, though, the NBTHK allows Hozon and Tokubetsu Hozon to be requested together at the first submission.

What each level demands, per the official text

The criteria are published; the version in force is the revision of 19 May 2015. In summary:

• Hozon: work no later than the Edo period with a correct signature, or unsigned (mumei) but with an identifiable period, province and lineage. Some tiredness or the odd flaw is tolerated if the blade is still worth appreciating, and repairs must not spoil the whole. From Meiji onward, only if signed and well made. Retempered blades (saiha) are rejected, except signed works by famous smiths no later than Nanbokuchō, of high documentary value and with little damage to blade and tang, which may pass with that noted. Doubtful cases are held over (horyū).
• Tokubetsu Hozon: among the Hozon blades, those of better workmanship and better preservation. Retempered blades are excluded, as are mumei works of the Muromachi and Edo periods, unless judged a superior work by a famous smith and in outstanding condition.
• Jūyō: among the Tokubetsu Hozon blades, those of particularly outstanding workmanship and good condition, comparable to an Important Art Object (jūyō bijutsuhin). Unsigned blades are admitted only if no later than Nanbokuchō; from Muromachi onward a signature is required, and from Edo onward, as a rule, an intact (ubu) signed tang.
• Tokubetsu Jūyō: among the Jūyō blades, those of outstanding workmanship, excellent condition and extremely high documentary value, equivalent to an Important Art Object or close to an Important Cultural Property (jūyō bunkazai).

Three rules common to every level: a large flaw that spoils the piece blocks a pass; works by living artists are not examined; and if a piece that already holds a certificate is submitted and fails, the result is «as is» (genjō) and it keeps the certificate it had.

Who judges: the NBTHK expert grades (den'i)

The NBTHK does not only examine swords: it also grants grades to those who study them. Its regulation on grades (伝位授与規程, den'i juyo kitei), as revised on 19 March 2015, sets four, applied for in order, one after the other, and each in two branches: blades, and mountings and fittings.

For anyone reading a paper, what matters is article 9: from okuden'i taigū upwards, the grade qualifies its holder to sit as a judge in the NBTHK examinations, 審査員 (shinsain); from chūden'i upwards, to act as an instructor of the society. The grades do not say who judges a given session, but they do say what anyone who may judge it has had to prove, in practical kantei tests and an oral examination.

Anatomy of a modern paper, field by field

The paper follows a fixed layout, in vertical columns read top to bottom and right to left. What follows is what a kanteisho (鑑定書) for Hozon or Tokubetsu Hozon carries; the shiteisho (指定書) for Jūyō and Tokubetsu Jūyō changes the title and the wording. The photograph is a real Hozon from 1996, with the signature and the number blanked out by its author, and the diagram numbers each field:

1. Title: 鑑定書 (kanteisho), top right.
2. Type of item: 刀 (katana), 太刀 (tachi), 脇差 (wakizashi), 短刀 (tantō)…
3. Signature: 銘 (mei) and the signature exactly as it is cut; if there is none, 無銘 (mumei) and the attribution.
4. Length: 長 (naga), in the traditional units — shaku (尺), sun (寸) and bu (分) — sometimes with 強 (kyō, “and a little more”). The one in the photograph reads 一尺八寸四分 (isshaku hassun yonbu), about 55.8 cm. To check it against the measured nagasa it has to be converted to centimetres: one shaku is 30.3 cm (see “Blade types”).
5. Level: it does not head the paper; it sits inside the formula that certifies the examination: “右は當協會に於て審査の結果保存刀剣と鑑定しこれを証する” (“we certify that the item on the right, examined by this society, is judged Hozon tōken”).
6. Date of the examination: Japanese era, year, month and day; in the photograph, 平成八年 (Heisei 8, 1996).
7. The society’s seal: under its name, 日本美術刀剣保存協會 (Nihon Bijutsu Tōken Hozon Kyōkai), the red seal, embossed: you can feel it with a finger, and it is the check most often cited against copies.
8. Number and split seal: top right, № and the paper’s number. Beside it, a red seal cut in half by the edge: a split seal (割印, wariin), stamped across the paper and the sheet it was separated from.
9. The blade’s tōrokushō: bottom left, in a box, the registration under which the blade was submitted: the prefecture (for example 東京都 教育委員会, Tōkyō-to kyōiku iinkai, the Tokyo board of education), the number and the date of registration. On an exported blade, it is the registration that was surrendered when it left Japan.
10. Perforated level: top left, in pinholes, the level abbreviated — 特保 (tokuho) on a Tokubetsu Hozon — and a figure.
11. Photograph of the tang: the photograph (or an oshigata, an ink rubbing) of the blade or its nakago, with its signature and its mekugi-ana, so it can be checked against the blade in front of you.

The paper itself matters too: it is good-quality washi, with a feel unlike a photocopy or an office printout, and that is part of what an expert checks before the text.

The old papers, and why they do not count today

The NBTHK did not invent the practice of putting a judgement on a blade in writing. From the Edo period on, the Hon'ami family — polishers and appraisers in the shogunate's service — issued their own origami: a folded paper with the attribution and, often, a valuation in money. The one in the photograph, dated Genroku 15 (1702) and signed by Hon'ami Kōchū, certifies a tantō attributed to Yukimitsu and records its valuation in gold. NBTHK papers, unlike these, say nothing about money; they judge the piece alone. The word origami — “folded paper” — comes from there, and is still used today for any sword judgement, NBTHK or otherwise.

The diagram beside this text numbers the level, the date of the examination (in the Shōwa era), the registration number and the seal of whoever examined the piece; the three paper colours are detailed in the table:

1. Title and level: the paper is headed 認定書 (ninteisho), and the level appears in the wording of the text; here, 特別貴重刀剣 (Tokubetsu Kichō).
2. Date of the examination: Shōwa era, between 1948 and 1982.
3. Registration number: specific to the session.
4. Seal of whoever examined it: a local branch or the head office.
5. Kichō ninteisho (貴重刀剣): white paper.
6. Tokubetsu Kichō ninteisho (特別貴重刀剣): green paper.
7. Kōshu Tokubetsu Kichō ninteisho (甲種特別貴重刀剣): blue paper.

In 1980 it came out that local branches had been passing items far above their merit, with organised crime involved. The branches stopped examining, and in September 1982 the NBTHK replaced every pre-Jūyō level with today's Hozon and Tokubetsu Hozon. Those ninteisho were neither converted nor revalidated: today they read as historical documents, not as attributions, and to hold a current opinion the blade has to go back to shinsa. Jūyō and Tokubetsu Jūyō, which were only ever issued by the head office, were untouched and are still trusted whatever their year.

Among collectors the argument is still alive: hundreds of thousands of papers were issued and many attributions were reasonable. But as a buying criterion a green paper supports nothing on its own, and resubmitting a middling blade usually confirms what was already known, or lowers it.

Going back to examination with a paper in hand

The NBTHK examination regulation (審査規程, shinsa kitei), as revised on 27 March 2023 and in force from 1 April, says what happens to the paper one already holds when the blade is submitted again. Article 23, paragraph 3: if it is submitted with the earlier paper (旧証書, kyū shōsho) and passes, the NBTHK collects that paper and issues the new one. And if the blade does not pass, the examination criteria settle it in one word, 現状 (genjō), “as it is”: the blade stays as it was.

Article 30, paragraph 2, contains a clause worth reading before submitting anything: the examination follows the regulation's own criteria and is not a commercial valuation, and so the NBTHK does not compensate commercial losses, such as a fall in market value, arising from its result. Whoever resubmits a blade to move up a level accepts that it may stay where it is, or come out worse, with no one to make it good.

The same regulation adds three practical points, useful for anyone who submits through an agent: the NBTHK may hold the piece while fees are unpaid or the earlier paper has not been returned; if nobody collects it within a year of the start of returns, it ceases to be responsible for its safekeeping, and two years after that it treats it as abandoned (article 31). And it may publish in its journal, in lectures and in exhibitions what it learns from an examined piece, with its photographs, but not the owner's name or address without permission (article 32).

Papers for koshirae and for tōsōgu

The same four levels exist for the complete mounting (tōsō, 刀装) and for loose fittings (tōsōgu, 刀装具), judged separately from the blade. A well documented piece can arrive with three papers: one for the blade, one for the koshirae and one for the tsuba.

The emphasis shifts. For fittings: works up to the Edo period with a correct signature, or unsigned but with identifiable period and school; from Meiji onward, good workmanship and good condition; cast pieces later than Meiji are rejected; and at Tokubetsu Hozon level, visible repairs or alterations, over-polishing that erases the colour of age, and illegible signatures all count against. For mountings: no tsuba, no pass, aikuchi aside; a missing kozuka or kōgai is accepted and noted; a rewrapped hilt does not disqualify if it harmonises with the rest; and foreign-made mountings are not examined.

How to read a paper

The certificate — kanteisho (鑑定書) for Hozon and Tokubetsu Hozon, shiteisho (指定書) for Jūyō and Tokubetsu Jūyō, and ninteisho (認定書) for the Kichō levels before 1982; by custom it is also called an origami, though strictly that name belongs to the old appraisals — reads right to left and gives, in columns: the type of item and the length of the blade, the signature or the attribution, the level awarded, the date of the examination and the society's seal. A photograph of the tang (nakago) is attached, and there lies the check that really matters: that this tang, its holes and that signature belong to the blade in front of you, and that the length matches the real measurement.

Two warnings. The paper is for the blade, not for the ensemble: a Tokubetsu Hozon says nothing whatsoever about the mounting that comes with it, nor about the quality of the present polish. And the attribution can change as the levels rise: an unsigned blade assigned to a school at Hozon may receive a different attribution at Tokubetsu Hozon.

How to verify a paper

A paper is checked in two different directions: that the paper itself is genuine, and that the paper belongs to that blade. Confusing the two questions is the costliest mistake.

That the paper is genuine. The association's seal is embossed, not printed: you can feel it by running a finger over it, and it is the first thing anyone who has seen hundreds of papers checks. The NBTHK keeps a register (台帳, daichō) of what it issues and checks it by telephone (台帳照会, daichō shōkai): all it needs is the paper’s number and its date of issue. For an important piece, bringing the blade and the paper together to the Tokyo office is still the definitive check. The register follows the paper throughout its life: on kanteisho and shiteisho that carry the holder’s name on the back (名義, meigi), that name can be changed; a damaged paper can be replaced; and if a shiteisho is lost, the NBTHK issues a substitute certificate (指定証明書, shitei shōmeisho), once only. Forgeries have turned up even of Hozon and Tokubetsu Hozon, the most common levels, so caution is not only a matter for old papers. People who handle many modern NBTHK papers point to further security features: a watermark with the society’s emblem visible against the light, tiny kanji almost the colour of the paper, a pattern of pinholes that differs between Hozon and Tokubetsu Hozon, and a tone of paper and envelope proper to each level. They are useful checks, but they do not replace asking the NBTHK itself.

That the paper belongs to that blade. This is where the photograph or oshigata of the tang that accompanies the paper earns its keep: check, one by one, that the number of mekugi-ana matches, that they sit in the same position, that the yasurime is the same, and that the signature — if there is one — reads the same in the photo and on the real blade. The length written on the paper has to match the nagasa measured on the piece; if it does not, either the paper is not for that blade, or the blade has changed since the examination. By convention, too, a tachi's signature and a katana's sit on opposite faces of the tang, so the face the mei appears on in the photo is also worth checking.

A paper without the blade beside it, or sold apart from it, is a reason to ask more questions, not fewer: the international market has seen genuine papers paired with a different blade from the one they certified. And it is worth remembering that a paper changes the attitude of whoever looks at the blade, not the blade: it remains what it is.

Other issuers and other documents

The NBTHK and the two NTHK are not the only bodies that put a judgement in writing, and it pays to know which document you are holding.

• Nihontō Bunka Shinkō Kyōkai (日本刀文化振興協会): founded in 2008 by a group that broke away from the NBTHK. It does not judge old blades: it issues certificates of new work for swords by living smiths and organises exhibitions of the sword crafts.
• Nihon Katchū Bugu Kenkyū Hozonkai (日本甲冑武具研究保存会): armour and other military equipment are judged not by the NBTHK but by this society, with its own five-grade scale.
• Invented societies: official-looking papers circulate in the name of Japanese organisations that do not exist, made to lend a blade an appearance of legitimacy. If the issuer is not one of the known bodies, the paper certifies nothing.
• Sayagaki (鞘書): the attribution an expert writes in ink on the shirasaya. It is a signed opinion, not a paper. As early as 1956 the appraiser Satō Kanzan (佐藤寒山, 1907–1978) warned that forged sayagaki bearing his name were circulating and urged buyers to judge by the blade and the signature, not the scabbard.

How the judgement behind any of these documents is formed, and what the tang tells beyond the signature, is covered in «Kantei: how to look at a blade».

What each level means for value

A paper does not set a price: it certifies a panel's judgement on a given date, and it is the market that decides how much to pay for it. Even so, the level shapes value fairly consistently, because it shapes rarity.

The calendar already hints at it: Hozon and Tokubetsu Hozon are examined four times a year; Jūyō, once; Tokubetsu Jūyō, once every two years, and only among what already holds Jūyō. Each step filters the one before it, so the population narrows fast. According to figures published for the fiftieth anniversary of the Tokubetsu Jūyō system, in 2021 there were 1,143 blades holding that designation, against the tens of thousands that hold Hozon or Tokubetsu Hozon: the gap in rarity between one level and the next is not gradual, it is a different order of magnitude, and the market reflects that in price more than in any other item on a listing.

The diagram beside this text numbers the shinsa cadence of each level and the extremes of rarity:

1. Hozon: four shinsa sessions a year.
2. Tokubetsu Hozon: four sessions a year, only for what already holds Hozon.
3. Jūyō: one session a year, only for what already holds Tokubetsu Hozon.
4. Tokubetsu Jūyō: one session every two years, only for what already holds Jūyō.
5. Base of the pyramid: the most common level.
6. Tip of the pyramid: the rarest level.

That said, each level plays a different role:

• Hozon is the threshold separating a seriously collectable blade from an unstudied one: it certifies that the signature or the attribution holds up, not that the piece is exceptional. It is, by far, the most common paper, and the first thing any serious buyer asks for.
• Tokubetsu Hozon picks out, among what is already approved, the better workmanship and the better condition; in practice it is the level most actively traded among collectors, because it combines relative availability with quality already filtered.
• Jūyō is the real jump: a single session a year, only for what already passed Tokubetsu Hozon, and a standard compared to a state-recognised Important Art Object. The international market treats the line between Tokubetsu Hozon and Jūyō as the one separating a good blade from an important one.
• Tokubetsu Jūyō is the exception within the exception: one thousand one hundred and forty-three blades in the entire history of the level, as of 2021. A paper at this rank approaches, in treatment and in price, an Important Cultural Property.

Two warnings against reading the level as if it were the price. First, the paper judges the blade, not the whole: a Tokubetsu Hozon with a tired polish or a poor mounting is worth less than an equally graded one that is well kept, and the paper says nothing about that. Second, the level is not final: a blade can be resubmitted years later and rise, if research on its school or its smith has moved on, or stay where it was if it fails — recall the genjō rule. And between NBTHK and NTHK, though both are serious bodies, the international market calibrates its prices on NBTHK figures; an NTHK paper does not simply translate into an equivalent NBTHK level.

The tōrokushō is not a certificate of authenticity

The tōrokushō (銃砲刀剣類登録証, jūhō tōkenrui tōrokushō) is the registration required by the Japanese firearms and swords law of 1958. It is issued by the prefectural board of education at monthly registration sessions, stays with the blade for as long as it remains in Japan, and obliges the owner to report a change of ownership within twenty days. The blade is registered, not its owner.

What it records is the length, the curvature, the number of mekugi-ana and what the signature says. It does not judge whether that signature is genuine, nor the quality, nor the date. Mistaking it for a paper of authenticity is the commonest error of first-time buyers, and Japanese listings often mention it as «Japanese registration included».

On export the tōrokushō is handed back and the Agency for Cultural Affairs (文化庁, Bunkachō) issues in its place an export inspection certificate for antiquities (古美術品輸出鑑査証明, ko-bijutsuhin yushutsu kansa shōmei). Items designated Important Cultural Property or National Treasure may not leave Japan. That is why a blade that reaches Europe legally comes without its tōrokushō: its absence says nothing, good or bad, about the piece.

The NBTHK paper records the tōrokushō under which the blade was submitted: the prefecture, the number and the date (see the anatomy of a modern paper, above). If the blade’s registration later changes, the NBTHK amends that entry on the paper at the owner’s request (登録証変更, tōrokushō henkō). On an exported blade, the registration shown on the paper is the one surrendered when it left Japan: it is normal for it not to match any current document.

The NBTHK in Europe

Outside Japan the NBTHK has a European branch, the NBTHK-EB (European Branch), and an American one, the NBTHK-AB. The European branch brings collectors and students together at regular meetings in different European countries, with courses, lectures, kantei exercises and hands-on study of important blades, and it translates parts of the journal Tōken Bijutsu into English. It starts from the same idea as the parent body: what is preserved are historical works of art, not weapons, and a blade’s value lies in the harmony of its steel, shape, hada and hamon, something learned only by seeing many good blades and reading the specialists. For a beginner in Europe it is the natural place to learn to look.