The Edo Shogunate's Standardization of Swords — Convergence on "Teisun" and the Social Order of Sword-Wearing by Status

The length of Japanese swords is inseparable from the fighting styles of each era. From the deeply curved tachi of the Heian and Kamakura periods, to the powerful nagamaki and ōdachi of the Nanbokuchō period, to the practical battlefield swords of the Sengoku period, the nagasa expanded and contracted in response to the shifting conditions of warfare. However, when the Edo period arrived following the unification of the realm by the Tokugawa house, the length of swords gradually converged under shogunal regulations, becoming organized around a certain standard measurement — "teisun." This standardization was not merely an exercise in weapons management; it was also an attempt to inscribe the status hierarchy of the samurai class into the physical object of the sword.

From the Battlefield to Sashiryō — How Peace Changed the Role of the Sword

During the Nanbokuchō period, large tachi with a nagasa of around three shaku (approximately 91 cm) were the primary weapons wielded by mounted warriors. However, as infantry combat by ashigaru spread during the Sengoku period, long tachi became difficult to handle. On the battlefield, suriage — the practice of shortening the nakago of an existing long tachi to reduce the nagasa — was carried out across the country, and the movement to refit such swords as more manageable uchigatana became widespread.

After Sekigahara, large-scale battles receded, and the samurai's sword shifted its center of gravity from a tool of the battlefield to sashiryō — a personal item that embodied social status. This was the fundamental condition that made the "standardization" of swords possible. Without warfare, the length of a sword could be determined not by utility but by social order.

The Shogunate's Length Regulations and Status-Based Upper Limits

The Edo shogunate set specific upper limits on the nagasa of swords worn by samurai, based on their status. These regulations tended to become gradually stricter with each change of shogun, and it is said that from the era of the fourth shogun, Tokugawa Ietsuna, onward, the upper limit for uchigatana was set shorter. Furthermore, fine-grained differentiation was applied, whereby those outside the samurai class who were specially permitted to wear swords — such as buke hōkōnin (samurai household servants) — were subject to shorter upper limits than regular samurai.

Summarizing this structure, the framework of the regulations was as follows.

• Samurai (hatamoto, gokenin, and domain retainers): uchigatana were standardized at around two shaku three sun, with an upper limit set
• Specially permitted individuals such as buke hōkōnin: a shorter measurement than the samurai upper limit was applied
• Farmers, artisans, and merchants (in principle): sword-wearing itself was prohibited, and no one could carry a sword without legitimate reason

This stratification shows that the length of a sword itself functioned as a visible indicator of status. Society was designed so that by glancing at the waist of a person passing on the street, one could read their approximate status from the presence or absence of a sword and its length.

Teisun and Suriage — Fitting Existing Swords to the Standard

In order to conform to the shogunate's length regulations, suriage — the practice of refitting the large tachi made during the Nanbokuchō and Sengoku periods to shorter lengths — was widely carried out from the early to mid-Edo period. The "teisun" for uchigatana was set at roughly around two shaku three sun five bu (approximately 71 cm), and it was not uncommon for ō-suriage to be applied, greatly shortening the nakago of old tachi to bring them within this range.

Suriage carries an unavoidable cost. The tōkō's mei inscribed on the nakago may be lost when the nakago is shortened. Many of the swords referred to today as "ō-suriage mumei" are swords that lost their mei in the process of being brought to teisun from the long swords of the Nanbokuchō or Sengoku periods, making it difficult to identify the exact maker. However, appraisal that estimates the period, school, and working range from the characteristics of the jigane and hamon of the blade is still carried out today, and there are many swords that retain their reputation as fine works even after losing their mei.

The expression "brought to teisun by suriage" is still used in sword appraisal and commentary today, confirming that this standard measurement was widely recognized throughout the Edo period.

Daishō — Displaying Samurai Status in Physical Form

The "daishō" — carrying an uchigatana and a wakizashi together — became established throughout the Edo period as a fundamental outward mark of samurai status. Wearing only a single uchigatana (two shaku or more) was called "ipponzashi" and was often regarded as the style of non-samurai. The very combination of wearing two swords was itself proof of being a samurai.

There was also a consciousness of appropriate measurements for the wakizashi (generally one shaku or more and less than two shaku) based on status and rank, and the balance of pairing a long uchigatana with a short wakizashi was shared as the basic form of the daishō. The appearance of wearing this combination at one's waist was part of the formal dress of samurai in public settings, an indispensable form for entering the castle, participating in sankin-kōtai, and formal ceremonies.

In addition to the blade itself, the shogunate also repeatedly issued regulations discouraging ostentation in the koshirae. Excessive metalwork and large tsuba were restricted, and attention was directed toward sword ornamentation in the context of promoting frugality in samurai life generally. This means that since the sword was a symbol of status, the dignity of its outward appearance was also tied to the maintenance of the status order.

Myōji Taitō — An Exception Marking the Outer Edge of the Order

In principle, farmers, artisans, and merchants were prohibited from wearing swords, but the shogunate and various domains would sometimes grant permission for "myōji taitō" (the right to bear a surname and wear a sword) to those who met certain conditions. This privilege, which permitted both the use of a surname and the wearing of a sword, was granted to village officials (nanushi, shōya, and others), wealthy merchants who contributed large sums of goyōkin, and those who had achieved notable accomplishments in scholarship, filial piety, or agriculture.

Those permitted myōji taitō could present themselves in local society dressed in the same manner as samurai, which meant gaining a degree of authority at the outer edge of the status hierarchy. This system also functioned as part of how the bakuhan system governed local society, serving as a means of incorporating those with economic and social power into the framework of order. It was precisely because the act of wearing a sword was not a purely martial means but a social status symbol that this system could hold meaning.

What Teisun Tells Us — A Perspective for Reading Edo-Period Swords

The Edo period's standardization of swords — the length regulations, the prevalence of suriage, the establishment of daishō wearing, and the myōji taitō system — all reflect the design philosophy of Edo society, which sought to manage swords in connection with the status hierarchy. As the role of swords shifted from actual combat to symbolism, their very "form" became a component of the social order.

When we look at extant Edo-period uchigatana, or at kotō that have been brought to teisun through ō-suriage, the status hierarchy of the time is quietly inscribed in the nagasa and the design of the koshirae. Behind a single sword with a nagasa fitting within the two-shaku-three-sun range, the status of the samurai who wore it, the shogunate's regulations, and the handiwork of the togi craftsman who performed the suriage are all layered together. When we turn our attention to the period of production and the nagasa while appreciating a sword, the social structure of the era in which that sword lived comes into view with surprising clarity.