- The Japanese sword is considered to be better than most other kinds of swords because of the materials used and the folding technique.
- The Japanese developed a special way of processing iron ore to make steels, soft inside and hard and sharp outside which is good for shock absorption.
- The tamahagane is made out of charcoal and iron ore. Heated in 2500 degrees and never completely melts, the soft steel with the low carbon level is made out of tamahagane.
- There are 4 different kinds of Japanese swords. The difference between them, tanto, wakizashi, katana and tachi, is the length (tanto is about 15~30cm, wakizashi is around 30~ 60cm, katana and tachi are longer than 60 cm). Tachi tends to be a little longer than katana and worn with a special belt and the tip pointing down. Katana is worn inside the sash usually with a wakizashi.
- The value of a Japanese sword is measured by how many times the steel is beaten and folded, the age, level of rust, damage and dents, detail of engravings on the tsuba and habaki and the popularity of the blade master.
- The date, name of the blade master and the clan where the blade master is from are usually inscribed on the tang.
- A Katana blade usually weighs around 750~950 grams.
- The hamon line is usually considered as the signature of the blade smith.
- It can kill only 3 people and then gets dull in a war.
- The blades that look like machete are not used for people but to cut the legs of the horses if they ran away.
- Most katanas have a blood groove to lighten the sword though it is said that the line makes it easier to keep the sword clean from the blood stains.
- The battles of Kawanakajima (1564) was the last war where only the swords used. Oda Nobunaga was first to introduce the gunpowder.
- The katana was famous in Asia, it was recorded that Japan exported 37,000 katana to China in 1483.
- Tokugawa Ieyasu once said, the sword is the soul of the samurai. Samurai used to name their sword and sleep with them.
- Sword had the highest importance in the Edo period, since there was no need to carry spears and bows. Also during the Edo period carrying firearms was banned.
- The quality of swords were tested on live criminals and their quality were inscribed on the blade (e.g. this blade cut through 3 bodies). So a good quality sword from the medieval times means it definitely had cut a human flesh.
- The Japanese katana may look simple but it takes 1 year to make a good katana and it has about 30 different kinds of processes. It starts with a Shinto ritual of warming up an iron stick by beating it and using the very hot stick to make a fire by using the rice leaves.
- After the WWII, the US army confiscated Japanese swords. It is claimed that there were more katana in the US than Japan in the 50s. Also during th WWII, Japanese generals surrendered by submitting their katana, not the pistol.
- Japan nowadays can export swords because they are considered art rather than a weapon. That is why Japanese katanas must be registered at the ministry of cultural affairs before they are exported to any country.
- The saying goes that, the samurai does not take out his katana from the scabbard but if it comes out, that means the blood will be shed.
N. Shang explains the samurai sword in more simple English as follows:
… If the iron is hard, it will snap easily and if it soft it will not cut so well. The combination of these contradictory qualities is the greatest achievement of Japanese forging and tempering techniques, whose three most important characteristics are as follows:
1 Hard outer skin is formed by folding over and hammering out the same piece of metal many times. This process aids the elimination of such impurities as phosphates and sulphates and also produces many layers (sometimes as many as one million) of metal of differing structure.
2 A softer inner core is formed by a different process of folding, using steel of lower carbon content, and the hard outer skin is wrapped around it.
3 A hamon is formed by covering the entire blade in a clay containing charcoal ash which is scraped away, in some places partially and in others completely, from the edge of the blade in the desired outline prior to heating. The varying thickness of the clay results in varying rates of cooling when the blade is quenched and these varying rates of cooling produce different crystalline compounds of iron and carbon…
The soul of the blade is believed to enter the sword at the moment the hamon is created. At this moment, the cleansing forces of fire meet the purifying properties of water and the sword’s soul is born. The sword emerges from the water changed. With the spirit, the sword now appears curved and complete.
If the sword smith fails to purify himself or his smithy, then evil kami can enter both the sword itself as well as the smithy. This could result in the production of cursed, or evil blades, meant only for killing. If, on the other hand, the sword smith is righteous and purifies himself and his smithy, he may produce blades that live up to their highest potential. (N. Shang: Kyoto Sword Museum)