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Evaluating and appreciating nihonto: Antique Japanese blades

Evaluating and appreciating nihonto: Antique Japanese blades

photo by Geekly Things

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In an earlier article ( Collecting, authenticating and appraising antique weapons ) we looked at the basic process for identifying antique Western swords.  Today we’re going to examine the basic process for identifying, appraising and appreciating nihonto, which translates as “Japanese swords”.

Rather than meaning any sword made in the general style of a Japanese katana, “nihonto” specifically means a blade made in Japan, and can include antique blades made prior to 1868, and blades made by modern smiths as art objects.  In fact, the term “art sword” is often applied to nihonto, and many collect them solely for the beauty of the form and appearance.

One of the largest and most prestigious sword judging organizations in Japan is the Society for the Preservation of Japanese  Art Swords (Nippon Bijutsu Token Hozon Kyoki or NBTHK. founded by the Japanese government in 1948,  with American and European branches).  A similar organization which also evaluates blades focuses on their condition and the historic merit;  The Society for the Preservation of the Japanese Sword (Nihon Token Hozon Kai or NTHK, founded in 1910).

As an aside, Japanese military swords produced after 1868 (Meiji Restoration) are known as gunto are not considered nihonto, but have their own collectors and aficionados.



Evaluating nihonto, known as “kantei”,  is a science — the sword long being an important part of Japanese culture — and thus is well defined and documented.  Somewhat  to the consternation of Westerners, the common language of nihonto terminology is Japanese;  however, there are extensive resources in the forms of reference books, online databases and helpful organizations to aid the beginning collector.

Lists of smiths and their styles of smithing have been cataloged, to the point that each smith’s trademarked signature, favoured sword styles, type of steel produced, and personal idiosyncrasies in swordmaking are known and can be identified.  A precise and lengthy lexicon of terms describes a blade’s length, curvature, form,  details of angle and geometry, blade thickness, length and shape of tang — even down to the type of file marks left by a smith — and so on.  With this information, an expert evaluator can simply look at a blade and know when, where, and very likely the school of smithing which produced the blade.

Just to show how long the Japanese have had an organized and cataloged method for evaluating swords, have a look at the Japanese Book of the Ancient Sword (free online), a treatise on evaluating swords originally written in 1783 by an unknown author and first translated into English in 1905.  This book tells the reader how to judge swords, what to look for, smiths and the type of blades they produced, where they were located, how to identify them, and provides a glossary of terms.

You’ll note I’m only mentioning the blade, and not the hilt, guard or other pieces of sword “furniture”.  They are considered ancillary to the nihonto itself, but are considered works of art in their own right, and have specialist collectors, often those who also collect nihonto.  Similar to nihonto, there are large technical lexicons describing shape, design and nature, with catalogs of smiths / artists, styles, etc.


Basic steps in evaluating nihonto

Much as was mentioned in the article on appraising Western blades, there is a step-by-step process which an evaluator follows.  First one must know what type of weapon you are examining:  a sword (katana or tachi), a short sword (wakizashi),  a long knife (tanto).  Other bladed weapons which fall under the nihonto class include the glave (naginata) or spear (yari).

Precisely what class a blade falls into is defined by its length, in Japanese measurement.  The Japanese system of measurement uses the following:

Shaku: 1 shaku = 30.3cm or 11.9 inches

Sun: 1 sun = 3.03 cm or 1.19 inches

Bu 1 bu = .3 cm or .119 inches

By definition, A katana or tachi is defined as being two to three shaku in length ( between 60.6 cm / 23.8 inches and 90.9 cm / 35.7 inches);  a wakizashi will be between one and two shaku in length ( between 30.3 cm / 11.9 inches and 60.6 cm / 23.8 inches), and a tanto less than one shaku in length ( less than 30.3 cm / 11.9 inches).

To make things easy, there are several Shaku conversion pages on the Web which can make your life easier.

An elementary system for inspecting a sword is suggested by Dr. Couthino in his paper (reference below):

“One learns from the very beginning that there is a correct way to examine a sword in order to identify the maker. The order is S for the shape of the blade, P for the pattern of the steel (hada) that can be seen in its surface, E for edge, that is the shape of the hardened edge (hamon), and T for tang (nakago). By shape the experienced collector knows that he has to decide if the sword is wide or narrow, thick or thin, if it is strongly curved or almost straight and so on.”

About the types of Japanese Swords: F. A. B. Coutinho, Japanese Sword Society of the United States, Vol. 40 #2 (2008)

Thus we have the mnemonic of SPET for this system.   It’s invaluable in identifying and therefore appraising a blade, and also for identifying fakes. A blade with a mix of shapes, geometries, edge styles and tang designs from different time periods and styles of smithing will almost certainly be a fake.  Let’s look at each of these elements  to see what they can reveal about the nihonto in question.



The shape of the nihonto has evolved over the centuries, with certain specific shapes, curvatures and geometries being commonly produced during different time periods.  As you can see from the following graphic (click to see the large version), the length of the blade, how deep the curve is, where along the blade the curve is placed, and how thick the blade is can indicate when it was made.


Japanese sword evolution

Click to see large version

These time periods are:

  • Jokoto: ancient swords, pre 900 AD
  • Koto:  old swords from around 900–1596
  • Shinto: new swords made from 1596–1780
  • Shinshinto:  new new swords. from 1781–1876
  • Gendaito:  modern swords, from 1876–1945
  • Shinsakuto: newly made swords 1953–today



Nihonto are made by folding the steel over and over until there are literally thousands of layers of metal.  This layering process creates a grain pattern on the blade’s surface, this pattern being known as hada in nihonto terminology.   The basic types of hada follow, and you’ll find excellent visual examples of hada on this site:

  • Masame: Mostly straight lines
  • Itame: Wood grain pattern
  • Konuka: Rice grain pattern
  • Mokume:  Whorls or knots (large or small)
  • Ayasugi: Wave-like pattern
  • Muji:  Such fine grains that the steel appears to have no pattern

Each smith, or lineage of smithing , is known to produce blades with certain types of hada; therefore this is a major clue as to the maker, school of smithing, and even location of manufacture of a blade.



The actual cutting edge of a blade is known as the ha.  However, the edge being referred to here isn’t the actual cutting edge, but the area of tempered steel near the ha, and most particularly the line which delineates the border between the tempered edge and the side of the blade.  This temper line and the pattern it forms is called the hamon.  Styles of hamon patterns have been used at different times and by different schools of smithing, so are a clue as to who made the blade.  Some smiths developed such individualistic hamon patterns that their blades can be easily identified, much like how a person can be identified by their signature.

There are quite literally hundreds of different hamon patterns listed in catalogs, but the main types are:

Hamon patternsSuguha (straight ) – Used from the beginning of Japanese sword manufacture to present day, by all  main schools with different variations. Essentially a straight line down the blade.

Midare (irregular) – Found from 1000 AD to present.  Irregular patterns characterized by mild curves.

Choji (clove) – Used from roughly 1100 AD to present.  Clove pattern, with bud-like extensions rising from the hamon line.

Gunome (zigzag): Found roughly from 1200 AD to present day. Characterized by angular lines.

Notare (waves): Sometimes known as billowing waves, this pattern has been in use since 1300 AD. The size and style of “waves” changes with different smiths and schools of smithing.

Hitatsura (full surface temper):  In use by one school of smithing since 1100 AD, but came into general use between 1337 to 1573.  Rarely seen after this period.



The tang, called the nakago in nihonto nomenclature, is extremely important in evaluating a blade, for a number of reasons.

First, it is never tempered or polished, thus the original metal remains as it was when first forged.  The condition of the surface helps to indicate age;  for example, very old blades have dark-coloured nakago due to the amount of oxidation of the surface metal.

Marking on tang indicating sword was used in tameshigiri on criminalsSecondly, the shape and length of the nakago are strong indicators of both time of forging and school of the smith, as the specific shape of the tang varied over time and with the designed purpose of the blade.  Additionally, various schools of smithing have been cataloged as using certain designs.

Thirdly, individual smiths and schools of smithing used specific methods for filing down the tang, leaving identifiable patterns of file marks behind.  The angle and strokes of the file marks are good indicators of the time period the blade was produced, the general school of the sword’s maker, and perhaps even the specific smith.  These markings are known as yasurimei

Fourth, when a smith signed a blade, it was always on the tang;  these signatures and other writing are called mei.  Often the date of forging would be included;  sometimes with additional information such as where it was forged, for whom, or who the artisans who polished the blade or made the sword furniture were.  In cases where the blade was tested through tameshigiri — test cutting through target objects to prove the sharpness and toughness of the blade —  the date, the amount cut through and the name of the tester would be included.

There were periods of time when the bodies of dead criminals were used as targets for cutting;  this information, along with the number of bodies cut through, was dutifully inscribed on the blade;  for more information on this, see my articles:  An academic look at the history of tameshigiri  and  A look at a dark past: forensic analysis of tameshigiri remains.


Appreciating the nihonto as art

Anyone can look at a finished, highly polished Japanese sword and admire the smooth lines, the depth of grain pattern visible on its sides, the brightness of the polish and design of the hamon.  With some knowledge, one can also look for perfection in the angle of lines, in the geometric curves, in its balance the proportions. With an in-depth knowledge, you can also appreciate the recognizable work of individual smiths, of the evolution of a school of smithing.

This is why you will find many Japanese swords on display as works of art in museums around the world.  Many are, in and of themselves, masterpieces of metalwork.

When dealing with a nihonto in poor condition though —  perhaps rusted or tarnished, nicked and worn — it’s harder to see the art of the smith.  It takes more knowledge and experience to recognize the value of such a blade,  though perhaps some people will find such a blade brings a closer feeling of history with it.

It should be noted that many old blades have minor-to-major flaws which reduce their value, or even totally negate it.  These flaws, as a whole, are known as kizu.


from Kizu visual glossary for beginners - discussion thread, The Japanese Sword Forum

from Kizu visual glossary for beginners – discussion thread, The Japanese Sword Forum


 A quick note on grading

While individuals can evaluate blades, the two organizations I mentioned earlier:  the Society for the Preservation of Japanese  Art Swords (NBTHK)  and The Society for the Preservation of the Japanese Sword (NTHK) both judge blades submitted to them.  When they find blades of value, they issue documents certifying their experts have inspected the blade and have given it a certain rating of artistic and historic value.  These papers precisely describe the blade, its dimensions, attributes (as discussed above) plus any special information pertaining to it.  These papers are known in nihonto terminology as origami (nothing to do with the art of folding paper into patterns).  A blade which has been authenticated by either of these organizations drastically increases in value.

The modern grades from the NBTHK are:

Hozon – Worthy of Preservation
Tokubetsu Hozon – Extraordinarily Worthy of Preservation
Juyo Token – Very Important Work
Tokubetsu Juyo  – Extraordinarily Important Work

The NTHK grades a nihonto using a point system for historic quality and perfection.  It issues origami with the following ratings:

Shinteisho – 60-69 pts – Genuine
Kanteisho – 70-84 pts – Important
Yushu Saku – 85-94 pts – Very Important Work
Sai Yushu Saku – 95-100 pts – Supreme Important Work

It’s often recommended that people new to collecting nihonto start by buying papered blades from recognized sellers.  It will cost more, but you are certain to get what you’re paying for.



So you want to learn?

If you want to learn about nihonto, there are many books and online information sources to help you, as well as several organizations you can join, depending on where you are located.  This is an subject best learned from someone who is already doing it;  look for a nihonto collector’s group in your area.

There are also a number of online discussion forums where members are always glad to help newcomers.

In the “Sources” section below you’ll find links to information sources, databases, web-based groups, national nihonto collectors organization in Japan, North America and Europe, and some of the most frequently recommended books for beginners.  These are only some of the many books, links, forums and databases which are available.




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