How to Tell if a Katana is Real

The Katana, a traditional Japanese sword, stands as a symbol of the samurai and is a testament to the exquisite craftsmanship of Japan. This sword, with a history that stretches across centuries, is highly regarded for its sharpness, durability, and the intricate making process. The Katana is more than just a weapon; it’s a piece of art, a symbol of a warrior’s honor, and a reflection of Japanese culture and history.

When we refer to a “real” Katana, we generally mean one of two things: an authentic Nihonto, or a functional sword that’s not just for display. An authentic Nihonto is a traditional Japanese sword crafted by a certified Japanese swordsmith, while a functional sword is made from high-quality materials and can be used for martial arts or cutting practices.

1) How to identify a real katana (Nihonto)

Identifying a Nihonto, a traditional Japanese sword, requires a discerning eye and knowledge of certain characteristics unique to these swords. These skills can not be learned from books on Japanese swords only, one must frequently attending study groups and appraisal meetings, taking real masterpieces and high-quality items in hand, and accumulating the experience of observing them with your own eyes, so you can know the characteristics of different schools and swordsmiths. This is not something that can be learned overnight.

But still, there are steps one can take to identify a real Katana (nihonto), here are some key points to consider:

1-Certification  鑑定書

A real Nihonto should comes with a certification. Several organizations and appraisers issue sword appraisal certificates, but the most reliable is the appraisal certificate of the “Public Interest Incorporated Foundation Japan Art Sword Preservation Association” 公益財団法人 日本美術刀剣保存協会.

If you have the certification, and the nakago matches the certification, that's a good sign of real katana (nihonto).

2-Mei-Signature 銘:

Authentic Nihonto often bear a signature or a seal (Mei) on the tang(nakago) of the sword, some typical types of Mei are: 1) The name of the swordsmith who crafted the sword and the date 2) The tameshigiri record of the katana on the mei "Tameshimei" (試し銘).  3) The owner's name "Shojimei" (所持銘).

The more valuable the sword, the more boldly the swordsmith engraves his own signature at the moment of forging the blade. A clear Mei is a good sign of real katana (Nihonto).

Be careful, some sword with famous swordsmith's signature might not be true, Mei could be falsify, it's called "Gimei" (偽銘). The intent behind this is usually to increase the perceived value or desirability of the sword.

It's also possible a katana has no mei, it is called "Mumei" (無銘).

3-Hamon-Temper Line 刃文:

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The hamon, or temper line, is a crucial aspect to examine. On a real Nihonto, the hamon is a result of the differential hardening (clay tempered) process and is embedded in the steel. The most important part to look at in appraisal is the “hamon” (blade pattern). When appreciating a Japanese sword, the first parts to look at are the 姿“sugata” (shape), 地鉄“Jigane” (ground iron), and 刃文“hamon” (blade pattern). From the sugata, you can guess the era, from the jigane, you can explore the transmission and school, and from the hamon, you can judge the individual swordsmith’s name.

Learning different types of hamon takes years of experience, but if you are expert of hamon, you have bigger chance to tell if a katana is real or not. For example, even if a famous swordsmith’s signature is engraved on the tang, but the hamon is collapsed and can be seen as impossible at a glance, it is a sign that it could be a fake katana. 

4-Nakago-Tang 茎

Nakago is the tang of a katana, and it's not visible when the katana is assembled with koshirae.  There are 3 things we can check on the nakago that will give you some clues about the authenticity of the sword:

The way the tang rusts and its color
Japanese swords, being made as far back as the late Heian period, naturally rust if left untreated. While the blade is kept rust-free through polishing for aesthetic preservation and storage, it is normal for the tang to have rust.

Therefore, when fakes are made in newer times, rust is artificially applied afterward. This rust, compared to the tang of older times, is not settled in its application and is characterized by not having the correct rust color that suggests it has aged. The correct rust color is a natural reddish-brown like chocolate, and it never turns black or purple.

Also, if there are unnatural aspects to the way the rust is applied, such as a rough feel, uneven color with rust spots, or straight boundaries between rusted and non-rusted areas, it is likely to be a fake katana. While rust is disliked from the perspective of blade protection, it is an important element in preventing fakes from circulating in the tang.

The Smell of the Tang

You might find it hard to imagine bringing your nose close to the sword to smell it. However, in the production of fakes, many chemicals were used to artificially apply rust, so a unique smell, different from naturally occurring iron rust, can be detected from the tang of a fake Japanese sword.

The Shape and Balance of the Tang

If a famous swordsmith’s signature is engraved but the balance between the blade and the tang is poor, or if the mekugi hole is in an unnatural place on the tang, they are signs of fake katana, because a real one don't leave these details unperfect. 

5-Other points

Serial Numbers: If there are serial numbers stamped on the blade, it is most likely a machine-made blade, such as a World War II gunto. These are not classified as “Nihonto”.

Blade Sharpening: Check if the blade is sharpened all the way to the base where it joins the hilt. Most World War II era blades are not sharpened all the way down to the habaki (collar). Some older (Shinshinto) swords may likewise not be sharpened down to the habaki; however, most World War II swords were not.

Quality of Fittings: On a real Nihonto, the fittings (koshirae) are usually handmade and of high quality. Low-grade metal mountings may indicate a non-authentic sword.

Seek Expert Advice: When in doubt, seek advice from a reputable collector or a sword club. They can provide valuable assistance in identifying an authentic Nihonto.

Remember, proper care and handling of a Nihonto are crucial to preserving its quality and authenticity for future generations.

2) How to identify if a katana is functional

If you are checking if a Katana is a real battle-ready sword, there are also several points you should check.

First, check the type of steel used. Real swords are always made from high-quality steel, such as carbon steel, T10 steel, or spring steel. Avoid swords made from stainless steel or other alloy steels, as they are not suitable for real swords.

Second, check if the sword is full tang. A full tang means that the blade extends into the handle, which gives the sword more strength and balance.

Third, check if the ito, or handle wrap, is tight. A loose ito is a sign of poor craftsmanship and can make the sword dangerous to use.

In conclusion, determining if a Katana is real involves checking various aspects of the sword, including the signature, the hamon, the quality of the fittings, the type of steel used, whether it is full tang, and the tightness of the ito. By carefully examining these points, you can determine whether a Katana is an authentic Nihonto, a real battle-ready sword, or a mere decorative piece.