Kotetsu School

Nagasone Kotetsu: Life and Career Transition

Nagasone Okisato (Kotetsu) is said to have come from Ōmi or from Echizen. He was born into a family whose trade was armor-making (kacchūshi), and in his prime he changed careers to become a sword smith, an unusual path. His birth year is unknown, and he was active in the early Edo period. His technical experience as an armorer, with its knowledge and skill in metal forging, working, and heat treatment, is considered to have directly informed his sword-making after the change. It is said that the fine texture of Kotetsu's jigane and the reliability of his quenching are not unrelated to this distinctive background.

Kotetsu is said to have moved to Edo at around the age of fifty. From around the Meireki to Enpō eras, for roughly twenty years, he made swords based at Shinobugaoka in Ueno, as inscribed on his blades: “Jū Tōeizan Shinobugaoka-hen.” His move to Edo coincided with the period's trend, in which the center of sword-making was spreading from Kyoto, Echizen, and Mino to Edo. Kotetsu emerged as an innovator who brought new energy to the Edo sword trade.

Kotetsu's Style and Reputation

Kotetsu is considered the greatest smith of shintō and, together with Horikawa Kunihiro of Yamashiro, is likened to the yokozuna of shintō. In the Kaihō Kenshaku (a sword-appraisal treatise) by Yamada Asaemon, dated 1797 (Kansei 9), he was ranked among the saijō ō-wazamono (highest grade of cutting ability). The “Edo Sansaku” (Three Great Edo Smiths) refers to Suishinshi Masahide, Taikei Naotane, and Minamoto no Kiyomaro, who were active in the late shinshintō period. Kotetsu is not included.

The most distinctive feature of Kotetsu's swords is their gunome-midare hamon. Large, vigorous gunome repeat continuously. The hamon has ko-nie that makes it bright and crisp, with abundant ashi and yō within the hardened zone, and sunagashi and kinsuji appear throughout, giving the blade a powerful visual impact. In particular, the juzuba (rosary-bead hamon), in which the gunome connect like beads on a rosary, is known as the hallmark of Kotetsu blades and is an important criterion in identification.

The jigane shows a fine texture of ko-itame-hada, tightly packed and spreading out, with evenly distributed ji-nie. The uniformity of the jigane, which Kotetsu, a former armorer, is said to have particularly pursued, is considered outstanding even among all Edo shintō.

Practical Performance and Cutting Ability—Kotetsu Blades in Combat

Another reason Kotetsu's swords are highly valued is their practical cutting performance. In the Edo period, tameshigiri (test cutting) was carried out on corpses, and it became customary to record the results on the nakago. Some of Kotetsu's swords are recorded as having cut through several bodies stacked together, such as sandō (three bodies) and yondō (four bodies). These records are regarded as evidence of exceptional cutting performance.

Later, Yamada Asaemon ranked Kotetsu among the saijō ō-wazamono in the Kaihō Kenshaku, which graded swords by cutting ability, and this also reflects the high regard for the sharpness of his blades. The combination of this practical ability and artistic perfection is the basis for placing Kotetsu's swords at the summit of shintō.

Kondo Isami and Kotetsu—A Legend of the Bakumatsu

Kotetsu's name shines in a special context in late Edo history. The fact—or legend—that Shinsengumi commander Kondo Isami (1834–1868) favored a Kotetsu sword played a significant role in spreading the reputation of Kotetsu blades to the common people during the turbulent final years of the shogunate.

The story of Kondō Isami keeping order in Kyoto while carrying a Kotetsu became widely known through kōdan (storytelling), naniwa-bushi (ballad recitation), and later films and novels. However, the accepted view is that the sword Kondō carried was not a genuine work of Okisato's but a forgery bearing a false signature (gimei).

Many forgeries of Kotetsu's signed works exist. Together with forgeries bearing the signatures of Tsuda Sukehiro and Inoue Shinkai, they are thought to number in the tens of thousands. This in turn proves the popularity and high value of Kotetsu's swords. The fact that forgers borrowed Kotetsu's name so widely shows the overwhelming authority Kotetsu held in the market of the time.

Okimasa and His Successors

Kotetsu's techniques were inherited by his disciples and successors. Nagasone Okimasa, Kotetsu's adopted son (also said to be his biological son), succeeded as the second generation and inherited the gunome-midare in his master's juzuba style. Okimasa is also regarded as a shintō saijō-saku (supreme shintō work) and a saijō ō-wazamono.

Modern Evaluation of Kotetsu Swords

In the present-day sword market, genuine Kotetsu works are traded at high prices and maintain a market value that is exceptional for shintō. In authentication, certificates from the Hon'ami family and from modern appraisal bodies serve as references. However, the complexity of the authenticity problem surrounding Kotetsu has not been resolved even today, and new appraisal research continues.

The "Kotetsu" swords that the men of spirit of the bakumatsu era dreamed of continue to live on today, with Kotetsu remaining one of the sword smiths that Japanese sword enthusiasts most desire to possess.