How to Clean a Japanese Katana and Saya
Swords of all types must be kept clean, protected and stored well to protect the blades from rust and corrosion.
The mirror-like surface of Japanese katana, require a little more care and special equipment when cleaning.
If dirt, oil or water build up in the saya (scabbard), the katana blade can be damaged very quickly. Wooden sayas may need to be replaced over time, as they soak up up the oil film from the katana blade during storage.
In addition to regular maintenance cleaning, a Japanese katana should be cleaned and oiled after each use.
How often should a katana be cleaned?
The katana should be stored with a very thin film of oil to protect against rust and corrosion.
Over time, even when stored in the saya (scabbard), the oil wears off and needs to be replenished. Moisture can also build up inside the saya, increasing the risk of the blade developing rust.
In a dry area, when the katana is stored correctly, this protective coating should be replaced every 3-4 months. In humid locations, a katana should be cleaned more often.
Cleaning equipment - a sword maintenance kit
Nuguigami - sword cleaning paper, usually made from rice, to wipe away dust and excessive oil from the blade. Soft, lint-free paper tissues, or even soft coffee filters may be substituted.
Uchiko ball - a silk ball on a stick containing fine stone powder for polishing the katana blade, removing fine scratches.
Soft cotton cleaning cloths or extra sheets of nuguigami.
Blade oil - a rust-preventing oil, commonly choji (mineral oil with a small amount of clove oil), or camelia oil.
Other mineral oils - weapons, sewing machine, gun or 3-in-1 oils may be substituted if choji oil is difficult to find.
Oiling cloth - any soft cloth that is not smooth or flat, such as non-starched flannel.
Sword cleaning kits are an easy way to purchase all the components you need to protect your katana. They include choji oil, nuguigami, and uchiko. Some kits, like this one, include the small brass hammer to remove pegs in the hilt, so you can also clean the tang of the katana.
Things not to do!
Never use harsh cleaning or polishing chemicals on a quality katana. These will damage the surface of the blade, and can cause rust and corrosion.
Never sharpen, clean or polish your blade with abrasive sharpeners or grinding wheels. If you do not have Japanese water stones for sharpening a katana, and experience or training, you can easily destroy your blade.
Never hold the blade with your fingers, especially when applying oil. Always use a clean cloth to hold the blade. It is both safer and protects the blade from being contaminated. Fingerprints left on the blade encourage rust to form.
Never clean a katana when you are distracted or ill, especially if the blade is live (sharp)!
How to clean the katana blade
Important: Pay careful attention throughout this process. It is very easy to cut yourself on a live blade!
1. Draw the katana carefully from the saya (scabbard).
Either continue to hold the katana throughout the cleaning process, or rest it on a soft, lint and dust-free surface to protect the blade and tip.
2. Remove the old oil and any dust from the blade by wiping with nuguigami (sword cleaning paper) or the soft cotton cleaning cloth. Use this paper once, then discard.
Pinch the nuguigami to clean in the groove (bo-hi) carved into the side of the blade.
Tip: Always wipe from the tsuba (hilt) to the kissaki (tip), keeping the sharp edge of the blade facing away from you, holding your fingers on the non-sharp edge.
3. Tap the uchiko ball a few times against both sides of the blade every 2-4 cms (roughly 1-2 inches), and the back, non-sharp edge, to leave a light film of polishing stone powder.
Use a second soft cotton cleaning cloth, or a clean sheet of nuguigami to rub the powder gently into the blade on both sides. This cleans and polishes the katana and absorbs any oil residue.
Repeat this step if small scratches or oily patches remain.
4. Use another clean sheet of nuguigami to remove any remaining stone dust from both sides of the blade.
5. Inspect the blade closely for any signs of rust.
6. Place a few drops of oil on each side of the blade, or drop some oil onto the oil cloth or nuguigumi sheet then wipe carefully and evenly on each side of the blade.
Tip: Use an eye dropper or a clean and dry glass rod to reduce excess oil.
7. Use another clean sheet of nuguigami to wipe away the excess oil, leaving only a thin film of oil evenly covering the katana blade.
Be careful when working around the habaki (hilt or blade collar) - you do not want any oily build up to damage the tsuba (hilt), especially if it is ornate.
8. Check the blade carefully (don't touch), to make sure the coating of oil is even and thorough.
9. Sheath the katana and return the sword to its display.
Cleaning the tang of a katana
To clean the tang of a katana, you must remove the blade from the tsuka (handle).
Traditional Japanese blades are held in the tsuka (handle) with a single mekugi (peg), made from aged and smoked bamboo. You can find bone or ivory mekugi in ancient katana.
Cast plastic handles, commonly used on modern replicas, will not be removable. Over time, with repeated use, the plastic handle will become loose. In this case, you will need to make (or buy) a new tsuka.
Mekugi are usually wedge-shaped and can only be removed from one direction. These pegs should be inspected regularly for damage. If the mekugi fails while you are swinging the sword, the sharpened blade could cause disastrous damage when it flies across the room.
There can be several separate components that make up the hilt of a Japanese sword. Each one needs to be removed carefully, and replaced in the correct orientation for the sword to fit snugly in its saya (sheath).
The components that can easily be damaged when disassembling a katana include:
- mekugi - the peg(s) holding the blade in the tsuka (handle).
- habaki - a metal or bamboo blade collar, keeping the blade tightly in the saya (scabbard), stopping the sword from rattling around, and preventing dust or rain getting into the saya.
- seppa - a hilt collar, typically made from bamboo, on just in front of the tsuba (hilt), protecting it from the saya.
Important: Disassembling and cleaning the tang of an expensive or antique katana to clean the tang can drastically lower the value of the sword. The rust on the tang is use to date and value heirloom katana.
1. Use a a small hammer, and a spike to carefully remove the mekugi.
You may need to shift the tsuka-ito (handle bindings) slightly to reach the mekugi.
Note: Many sword cleaning kits come with a small brass hammer with a pin screwed into the top.
2. Clean the tang in the same way as you cleaned, polished and oiled the katana blade.
3. If any of the components in the hilt are damaged, replace them before reassembling and storing the katana.
Disassemble and clean a katana
Cleaning the katana handle - tsuba
The discoloration and dirt on the handles of an old and antique katana should not be cleaned. This helps to date the katana and forms part of its history.
1. Clean dirt from the handle and wrapping threads with a toothbrush, water and a gentle soap that leaves no residue (pure soap, woolite, or soap for cleaning silk). Scrub gently to avoid fraying.
In older times, samurai considered the tsuba to be disposable, replaced when too dirty or worn from use.
Note: Be careful not to get any water on metal fittings or near the blade, as it will cause rust! It is safer to do this when the katana has been disassembled.
2. Dry the tsuba quickly using absorbant microfiber towels and a dry location.
3. Ensure the tsuba is completely dry before reassembling the katana.
How to clean a katana saya
Wipe the outside of the saya (scabbard) with a soft, dry cloth.
If the saya is wood, and has been protected with wax, polish it occasionally with wax to maintain the protection against water and cracks.
After drawing the katana for cleaning, tap the mouth of the saya (koiguchi) on a somewhat hard surface gently to loosen any debris.
Use a thin long piece of steel, wrapped in a fine cotton cloth to carefully clean inside the saya.
Help - I have rust on my katana!
If you have an antique or expensive katana that was made in Japan, find a katana expert who can repair the damage and polish the blade. You may need to send the sword back to Japan for professional restoration.
If you have a cheaper katana, and you don't mind the surface losing some of its mirror finish, these methods can remove rust.
Removing rust from a katana
For light staining: use extra uchiko powder and rub harder to remove the spots.
For surface rust: use 1500-2000 grit wet-dry sandpaper, working on a tiny section of the blade at a time. Make sure the blade is secured to a flat surface, and facing away from you.
For deeper pitted rust: use a wire-bristle brush to remove the majority of the rust dust. Use a little WD-40 and very fine wire scrubbing pads to scratch out the rust.
Once there is no discoloration left, clean as for surface rust with extra-fine wet-dry sandpaper.
Make sure you protect the blade after treating the rust with mineral oil before storing!
Did you know ... ?
Displaying a Japanese katana with the tsuka (handle) on the left, indicates peace.
When the tsuka is on the right, the katana is ready for battle - easily able to be drawn.
Storing the katana
Store Japanese swords in a clean saya (scabbard), with a thin film of mineral oil on a clean blade.
Lay the sheathed katana horizontally on a stand, and ensure the sharp edge is facing upwards.
Storing a katana at an angle or vertically, will cause the protective oil to pool at the tip of the sword, damaging both the blade and the saya.
Do not store in locations with extreme hot or cold temperatures. These can damage both the saya and the katana blade.
In locations with moderate to high humidity, check the blade every week or so for signs of rust.
If you are displaying a cheaper katana with a naked blade, protect the blade with a thin layer of