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July 16, 2020

Inspecting Your Japanese Sword

By Ryan F. Sullivan

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Among the non-gun inventory that passes through Rock Island Auction Company, swords are among the most interesting. Japanese swords, in particular, are a topic of great interest and variety, running a whole gamut from common sidearms to actual global treasures. Many American soldiers brought these swords home with them after returning from World War II, often without much background on the history or origin of the blade. Some were quite literally taken off the bodies of their former owners and others were found in large stockpiles left behind by surrendering soldiers.

Japanese swords are more than just katanas and samurais. Made in a variety of lengths for different tasks, these revered blades have a place of honor in the very foundation of Japan. They remain symbols of strength, poise, beauty, and savage combat.

Following the war, rules and regulations brought in by the Occupation Government set a very strict standard for what could be considered a cultural artifact to be preserved and what was a weapon to be destroyed (and if not for the intervention of leading scholars, they all would have been destined for the scrap pile). As a result of these two factors, it is generally easier to find a katana in the United States than it is in Japan, with some makes and models even being illegal to own in their homeland. Even today, Japanese swords and knives are still being recovered and reintroduced into the market.

Beautiful collection of Japanese Swords

Where to Start?

When inspecting a Japanese sword, there are a number of critical points to keep in mind. First, in contrast to European and American designs, traditional Japanese blades often have no special protection from corrosion or elemental exposure. While some later swords (typically mass produced models) can be seen with protective coatings of nickel, a traditional blade is highly vulnerable to damage from corrosion. In addition to being mindful of environmental factors (fluctuations in humidity in particular), it is critical to keep any hands off the bright section of the blade. The salts and oils in human sweat are very bad news for the blade, and can be capable of doing visible damage to the surface in a relatively short time.

Second, all internet jokes aside, Japanese swords tend to be notably sharper than European style blades, and should be treated with appropriate caution. Some elements of the following instructions involve contacting the blade, which by nature involves an element of unavoidable danger; the reader proceeds at their own discretion. If there are any doubts about the interpretation of these instructions, or in the ability to execute them, DO NOT PROCEED.


Lot 253: Signed Wakizashi Length Japanese Blade with Papers

In contrast to the traditionally permanent assembly of a rapier or cavalry sword, Japanese swords are made so the end user can easily take them apart. The hilt of a katana or wakizashi is typically secured with one or two pins or, in later swords, bolts. Before attempting to draw the sword, check that this pin is in position and secure. Failure to do this could result in pulling off the hilt and leaving the blade behind, or worse, drawing the sword only to have the blade fall out. Additionally, refrain from any sharp or swift movements of the sword until confident that everything is together, properly secured, and appropriately tight.

Typical Japanese sword and sheath, or saya.

Japanese swords are often found in a sheath (or saya), which is typically constructed from two pieces of wood shaped to fit the blade, glued together with a seam running parallel to the sword's edge and spine. Some might have additional leather coverings, but this is not often a "load bearing" component, in contrast to common American swords. Due to this construction, there is a real and present danger of the sheath splitting along this edge when attempting to withdraw the sword or during accidental rough handling.

For safety, ensure that a personal space bubble is clear of spectators (lest one deliver a swift elbow to an overly curious face when a stuck blade suddenly loses friction), hold the sword oriented in an edge-up posture, and grip the sheath from the bottom, being careful not to wrap any fingers around the top; this will keep any fingers out of harm's way in event of a sheath failure. By keeping the edge upright, chances of the skin of the blade being rubbed against unseen debris trapped in the sheath can be reduced. If the sword does not come out with gentle pressure, check for a retention device; these are sometimes seen on military-pattern swords and can be disengaged with a spring-loaded button immediately below the guard.

What To Do About Oil?

Once out, it is not uncommon to find protective grease or other storage residues on a Japanese sword. While not the "according to Hoyle" traditional way to store them, coating the blades in grease or oil was the best method known to those bringing the swords home to the States after the Second World War. Other times, there will be a light coating of oil on the blade, which is a more proper style of protection. Even if these coatings are not removed, a basic check of the blade can still be completed. If humidity is a problem in storage spaces and regions, consider leaving the oil where it is.

Lot 255: Japanese Sword

While less prone to flexing than Western swords, it is still worthwhile to check; sword in hand (with space bubble appropriately cleared), extend the tip towards an available light source, edge up, and look down the edge of the blade. Any significant deviation in the line of the blade is more noticeable in this orientation than attempting to view from the side, and any serious chips in the edge can be seen in any odd reflections of light. Edge and tip chipping is a common issue with Japanese swords due to the very high hardness (at the cost of ductility) of the materials used in that section of the blade. While unsightly, these chips are part of the history of that particular blade.

Cleaning Japanese Blades

To clean the blade of a Japanese sword for deeper inspection, two things are needed: some manner of lint-free paper and an appropriate light oil. For those seeking the "official" stuff, there are kits online for rice paper and "choji" oil for reasonable prices, which are nice. Alternatively, coffee filters make a good substitute for the paper, and a number of different oils can be used in lieu of choji such as basic mineral oil or a number of other light lubricants such as RemOil (as used here at Rock Island Auction Company).

Cleaning of the top portion of the blade using a coffee filter.

The first passes on the Japanese sword blade should always be dry, to remove any material transferred to the blade by the sheath. With a dry piece of paper in hand, rest a thumb against the spine at the very bottom of the exposed steel; the thumb will serve as a guide for the rest of the hand,protecting any fingers from accidentally making contact with the cutting edge. Thumb securely in position, lay fingers along the side of the blade, and in a smooth motion bring the paper down the length of the blade, taking care not to allow the angle of the hand relative to the blade to shift. Best practice in these cases is to discard the paper on each pass or, if large enough, shift the used position to ensure any debris or old oil wiped off isn't rubbed back onto the blade.

Once the old material is removed, oiling the blade follows a similar motion, using an oiled paper instead of a dry one. Applying oil directly to the blade is not recommended. Some cleaning kits come with a polishing compound, however, the use of this compound is not strictly needed for a basic cleaning and will not be discussed here.

In contrast to an American-made knife, sharpening or honing a Japanese sword blade is NOT a casual part of maintenance. Do NOT attempt to use any sharpening or polishing tools on a Japanese sword blade. Polishing or sharpening one of these blades is both a skill and an art, requiring specialized tools and techniques, and not an exercise for the untutored or the faint of heart. A true expert, properly trained and equipped, is capable of delivering impressive results, but anything less could destroy the sword.

Cleaning the alternative side of the blade with the use of a coffee filter.

Below the Blade

Once the blade has been seen to, the hilt and fittings follow. On a traditional Japanese sword, the fittings can be as much a work of art as the blade and could involve specialized artisans and interesting materials. Though designed to be removed, the installation of the blade to the hilt should be rigid. When fully assembled, the sword should move and feel like a single unit. If the sword feels loose or rattles when handled, it could indicate that something is worn or absent. Immediately below the blade should be a metal collar, which interfaces with the throat for a tight fit. Check this collar for splits and chips, as it is a common point of stress and failure.

Typical hilt found on many Japanese swords.

Below this should be the guard (tsuba), and a number of metal spacers (seppa). These parts serve both a decorative and functional purpose, the former to contribute to balance and ensure that the hand can't slip off the grip onto the blade during rough handling, and the latter to ensure that there is no play in the components. Seppa can be easily lost or mislaid while the Japanese sword is disassembled, and such loss is a common cause of looseness in the fittings. Further back, the grip is typically constructed with either a core of wood, shaped and fitted to the tang of the blade, a wrapping of rayskin for texture, or a length of cord wrapping, for additional purchase in the hand and to secure ornaments (menuki), which in turn also assist in the grip. Staining or wear of the cord is the most common issue on the hilt, due to exposure to the elements and a tendency to absorb oils from the user's hand. Removal of a Japanese sword blade from its fittings can be accomplished with simple tools, but is not recommended for casual inspection.

Examples of saya, tsuba, seppa, and menuki found on Japanese swords.


Japanese swords are very interesting, not only because of their distinctions from typical European and American blades, but also because of their fragility contrasted against their strength. While a symbol of the power and might in Japanese culture, these blades must be carefully preserved and cared for so not to completely ruin them. While it is possible, and even fun, to treat these swords at home, extreme caution must be practiced so that serious injury can be avoided. Please take care and be mindful of surroundings as well as others nearby. As always, please contact Rock Island Auction Company for any questions or advice on how to properly handle, store, and restore traditional Japanese swords. With great care, these treasures can, and do, remain in pristine condition for centuries.

Lot 254: Signed Japanese Sword

Rock Island Auction Company is no stranger to traditional Japanese swords, and they can be found in our Online, Sporting & Collector, and Premier Auctions alike. If you are interested or curious about consignment opportunities, please contact us through the company website.

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