Nagasone Kotetsu — The Armourer Who Became a Master Swordsmith

As the name of a sword, it may be the most famous in Japan. Kotetsu. The man who forged them was Nagasone Kotetsu, a smith working in Edo.

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Who Was Nagasone Kotetsu?

Kotetsu was a swordsmith of the early Edo period.

In the vocabulary of Japanese swords, blades made after the beginning of the seventeenth century are called shinto (shintō), "new swords." Kotetsu is regarded as one of the very best of them.

His work is characterized by cutting performance and durability. Some surviving blades carry inscriptions recording the results of cutting tests, which indicates that performance was the selling point.

How Nagasone Kotetsu Turned From Armour to Blades

The striking fact about Kotetsu is that he did not start as a swordsmith.

He worked in Echizen as an armourer, making helmets and body armour: forging iron into protection. The Nagasone smiths are understood to have moved to Echizen from Omi, and his own birthplace is not established.

He later moved to Edo and switched to forging swords. The change is usually placed at around the age of fifty — extraordinarily late for a smith.

The same metalwork, redirected from a defensive object to a cutting one. The long peace had reduced demand for armour, which is generally taken as the background.

And despite the late start, his blades reached the top rank.

Why Are There So Many Fake Kotetsu Blades?

No account of Kotetsu can avoid the forgeries.

There is a saying in the sword world to the effect that any Kotetsu you see should be assumed fake, and a signature alone establishes nothing.

The reason is straightforward: the work was esteemed and expensive. He forged for some twenty-five years and left a substantial body of work, and it still did not meet demand.

Authentication remains specialist work today.

Was Kondo Isami's "Kotetsu" Genuine?

The name reached the general public largely through Kondo Isami, commander of the Shinsengumi.

After the Ikedaya Incident, Kondo wrote home that while his men's blades were damaged, his own had come through undamaged — because, he supposed, it was a Kotetsu. That line made "Kondo's Kotetsu" famous.

Whether the blade was a genuine Kotetsu has long been doubted.

The reason is the one above: Kotetsu blades were already extremely expensive and widely forged. That the man who had inherited the Shieikan dojo in Edo could have obtained a genuine one is considered unlikely by many.

How much Kondo himself knew about it is unknown.

The episode does illustrate the smith's standing precisely. When you wanted to say you owned a fine sword, Kotetsu was the name you reached for.

Surviving Kotetsu Blades Today

Blades by Kotetsu survive with designations as Important Cultural Properties and Important Art Objects, and can be seen in museums and sword exhibitions.

In recent years games and stage productions about swords have made the name familiar to younger audiences. The characters presented there are inventions, and have nothing to do with the record of the smith himself.

About the man, neither his year of birth nor his birthplace is known. Omi is proposed as his origin, and he is documented as an armourer in Echizen. He is thought to have died around 1678.

Nagasone Kotetsu Timeline

For the man who carried one, see Kondo Isami; for the sword world of the Bakumatsu, the fencing schools.