The maintenance of your Japanese Katana or Samurai Sword, Nihonto, Wakizashi, Tanto or Naginata is very important to keep them in good condition.
Of course you have more Japanese weapons as well, I will especially quote the katana or samurai sword, but I also mean other Japanese weapons, such as wakizashi and tanto. Today, rust is one of the most important enemies for your sword . It is therefore very important to maintain it well and therefore regularly put it in the oil so that oxidation has no chance. The iron and carbon steel reacts with oxygen in the air and will sooner or later rust if not properly protected with oil.
A thin layer of oil on the blade ensures that the steel does not come into direct contact with the air and will ensure that they do not react to each other. Water or moisture together with acids, which may have come on the blade with fruit tameshigiri also ensure faster oxidation. This must also be removed before new oil is applied.
Make sure your sword is not displayed in an environment or is stored with very large temperature fluctuations. Because if your katana is just above a radiator, your oil will dry up very quickly. In a normal living room temperature once every three months will be sufficient, keep an eye on it, if your sword starts to rust this is hardly to stop.
My advice is to prepare everything in advance before you start so that you can carry out everything with full attention and safely. In this way, accidents cannot happen quickly.
You need the following products to apply the oil:
1) Clean cotton cloths or ricepaper for cleaning
2) Small cotton cloth for applying the oil
3a) Choji oil (or another neutral mineral oil)
3b) or Break free oil, I personally recommend this for both katana and nihonto
4) quiet place with possibly a standard
I mention two oil possibilities, the Choji oil is traditionally used and is great to use. This is a neutral mineral oil with a small percentage of cloves. What I personally do not recommend to use with a Nihonto are the Uchiko ball with powder which is suitable for light polishing, because this contains powder from the Uchigomori stones and this can cause minor damage to the blade or polishing. You can often find this type of accessory in a standard maintenance set.
The Break Free oil is a modern oil from the US Army with excellent properties, it protects long-term against long-term protection against dust, dirt, sand and is temperature-insensitive so that the oil always remains the same thickness and does not cure and protects against corrosion for 5 years. This oil therefore ensures that the steel is well protected against external influences
First, gently pull the katana from the saya with cutting edge away from you and place it next to or in front of you or place it temporarily on a stand.
So you keep the saya, you put it away for a moment. It is quite possible if you use the katana often that some dirt has ended up in the saya. You make a cushion with the cotton cloth (1) and gently tap the koiguchi or opening of saya on it. Any dirt or fibers will now fall out of the saya, if you use a katana as a decoration this is not necessary to do.
Then you put the saya quietly away, possibly you now put it on the stand.
Now grab the katana with the right hand and with frequent use you can now view the blade with the support of a cloth. If your katana is mainly decorative, this is not necessary. Now remove the old oil with the cotton cloth (1) of ricepaper, do this from the mune (back) of the blade. Apply slight pressure and also take the bo-hi with you. Start from the side of the tsuka (handle) at the height of the Habaki and gently move with light pressure to the kissaki (point). When this is done you can apply new oil. Again put your katana down so that you can grab the cloth you need.
In many cases the Uchiko ball is now used, you do not have to do this if your sword is only on the stand. With a Japanese sword that has become quite dirty during a tameshigiri session you can think about doing it anyway. With a more expensive high end katana or Nihonto I will not just recommend using this because of leaves and polishing damage that may occur. If you still have dirty spots on your sheet then you better remove this with alcohol. I do recommend using an alcohol percentage of 99.5% or higher, you can buy this at the drugstore or model-making stores.
The powder from the Uchiko Ball comes from the uchigumori polishing stone. The powder from the Uchiko ball absorbs the possible moisture and oil also ensures a very light polishing. Tap the blade several times and work from the handle to the tip. Do this on both sides of the sword and don't forget the back. You remove this powder with rice paper, do not apply pressure to the leaf and of course finish off with the cut.
Now you can apply new oil (3a or b), put some drops on the clean cotton cloth (2). You can now apply the oil by wiping the cloth with light pressure. You now start again from habaki to the kissaki, always keep the cutting edge away from you. You can often see under the light whether all areas are covered with a new layer of oil.
Now gently insert the swordblade into the saya, lean on the back of the blade and store everything safely again.
A professional sword maintenance kit contains all parts for a thorough cleaning and a necessary new layer of oil.
Below you can see exactly how this works!