Introduction
Japanese swords of the Jōkotō period – literally “ancient swords” – encompass all blades produced up until around the end of the 9th century CE. These early swords established the foundation of Japan’s sword-making tradition. In contrast to the elegant curved blades of later eras, jokotō were characteristically straight in form. Both double-edged tsurugi (剣) and single-edged chokutō (直刀) appeared in this period, often directly inspired by continental prototypes. Historical evidence suggests that early Japanese swordsmiths learned their craft through contact with China and the Korean peninsula; iron swords and forging knowledge entered Japan during the Yayoi period (c. 300 BCE – 300 CE) via these routes. As a result, the basic style of jokotō closely mirrored ancient Chinese swords, and many were initially made by immigrant craftsmen or using imported metal. These swords were typically worn hung from the waist on a belt, and used by infantry for thrusting stabs or slashing cuts. This chapter provides a detailed examination of jokotō, exploring the metallurgy and forging techniques of the time, their cultural and ceremonial roles, notable archaeological finds (and their state of preservation), and the distinctive styles, inscriptions, and mountings that define these ancient blades.
Metallurgy and Forging Techniques in the Jōkotō Period
Early Japanese sword-making was a developing art, blending imported techniques with local innovation. In the initial stages, swordsmiths in Japan forged blades to imitate Chinese models, but they had not yet perfected the sophisticated heat-treatment that later eras would achieve. Contemporary chronicles note that many early chokutō had “faulty tempering”, suggesting the hardening process (quench) often produced uneven or brittle edges. In practice, these straight swords functioned more as robust hacking weapons than finely honed slicing blades. Over time, however, the craftsmanship improved markedly. By the 5th century, smiths were intentionally refining and folding the iron multiple times to purify it – a fact dramatically recorded on an ancient blade itself. The famous inscribed sword from Inariyama Kofun boasts that it is a “well-wrought efficacious sword” fashioned with “hundred-fold” forging. Such wording (百練利刀) implies repeated hammering and folding of the metal to toughen the blade and eliminate impurities, showing that the principle of layered steel construction was understood in the Jokotō era.
The raw material for these swords was iron produced by early smelting furnaces or sometimes imported as semi-processed metal. Archaeometallurgical analysis has revealed fascinating clues about resource sourcing. For example, the Inariyama Sword’s iron was determined to have been smelted from copper-bearing magnetite ore originating in the Jiangnan region of China. This implies that ingots or iron blooms were brought into Japan and then forged locally into swords. By the 6th century, Japan developed its own indigenous steel-making method – the tatara furnace – in regions like Kibi (western Honshu). This low, box-shaped clay furnace, distinct from Chinese and Korean designs, allowed for the production of tamahagane (high-quality carbon steel) from iron sand. Although true tatara steel would later enable the highest quality blades, even in the late Kofun period smiths could produce serviceable steel. They often combined different iron materials to create a blade: a softer low-carbon core for toughness and a higher-carbon outer skin for a sharp edge, forge-welding them together in what would become the classic Japanese sword lamination technique.
Forging in this ancient period was labor-intensive and already held ritual significance. Swordsmiths worked by heating the iron in charcoal forges and hammering it repeatedly to homogenize the carbon content and drive out slag. In some cases, trace elements present in the iron gave these swords unique properties. Historical analyses suggest that certain jokotō contained copper or nickel, hinting at the use of meteoric iron or specific ore sources. While exact techniques varied by region and time, the smiths of the Kofun and Asuka periods clearly grasped the essentials of blade-making. They achieved reasonably hard cutting edges (through quenching in water) even if the temper lines (hamon) were not yet the artful, controlled patterns seen on later samurai swords. By the late Jokotō era, forging methods had advanced enough that swords were not only functional weapons but could also carry intricate inlays and inscriptions, attesting to the metallurgical skill of their makers. In short, the metallurgy of jokotō evolved from simple imitative ironworking into a distinctly Japanese craft, setting the stage for the masterpieces of subsequent periods.
Cultural and Ceremonial Roles of Ancient Swords
From their earliest appearance, swords in Japan carried deep cultural and spiritual significance beyond their utilitarian function. The importance of the sword as a symbol is cemented in Japan’s foundation myths and earliest records. Notably, one of the Three Imperial Regalia of Japan is a sword – the legendary Kusanagi no Tsurugi – which, according to tradition, was handed down from the gods. This demonstrates that by the time of the 8th-century chronicles Kojiki and Nihon Shoki, ancient swords were regarded as sacred objects. In these texts, swords are not only weapons but also divine treasures and tokens of authority. High-ranking chieftains and kings in the Kofun period are frequently associated with famed swords, and being presented with a fine sword was both a political and religious act.
Archaeology confirms the ceremonial value of jokotō. Many of the grand Kofun-era tombs (tumuli) of the 4th–6th centuries have yielded swords as grave goods, placed alongside the departed elite as symbols of power in the afterlife. These burial swords were often lavishly adorned, indicating they were prestige items. For example, some blades were found sheathed in scabbards with bronze fittings or wrapped with precious metal foils. The practice of inscribing swords with text, which emerged in the 5th century, also points to a commemorative or ceremonial purpose. In China and Korea, contemporaneous swords sometimes bore auspicious phrases or calendrical inscriptions meant to ward off evil. Japan adapted this custom but made it personal: inscriptions on Japanese jokotō of the 5th–7th centuries often include the names of individuals, their titles, and even the sword’s smith or donor. Such inscriptions could sanctify the sword as a bearer of the owner’s legacy or as an offering to the kami (deities). In other cases, a sword’s inscription might invoke divine protection. In either case, the act of engraving text into the blade in silver or gold inlay elevated the sword from mere weapon to cherished artifact laden with meaning.
Apart from funerary contexts, straight ancient swords figured prominently in religious rites and state ceremonies. Shinto shrines have long treasured ancient swords as shintai (sacred objects). A striking example is the Seven-Branched Sword (Shichishitō), a peculiar iron sword with six protruding branch-like arms, which was presented by the king of Baekje (Korea) to a Yamato ruler as a gift of friendship or alliance. This sword, believed to date to the 4th century, was never intended for combat; its design is entirely ceremonial. It has been preserved since antiquity at the Isonokami Shrine in Nara, where it was revered and carefully stored (and notably not displayed publicly). The Shichishitō’s inscription, inlaid in gold, invokes the relationship between Baekje and Yamato, underlining how swords could serve as diplomatic and sacred tokens. In Shinto practice, offering swords to deities became an established tradition. At the Ise Grand Shrine – the holiest Shinto site – a pair of straight swords known as Ontachi are made and dedicated to the sun goddess Amaterasu every 20 years as part of the shrine’s renewal ceremony, a custom said to date back to at least the 7th century. These offerings are exquisitely crafted chokutō with elaborate mountings, created not for battle but to honor the deity.
In the nascent imperial court of the Asuka and Nara periods, ceremonial swords were worn by officials as markers of rank and were used in imperial rituals. Literary sources and tomb art (like haniwa clay figures) depict dignitaries wearing straight tachi at the hip during formal occasions. Thus, jokotō were imbued with layers of significance: they were instruments of war, certainly, but equally emblems of sovereignty, martial spirit, and divine favor. Through ritual and tradition, the ancient Japanese sword transcended its material form to become a core symbol in the cultural identity of early Japan.
Notable Archaeological Discoveries and Preservation
Because iron is highly susceptible to corrosion in Japan’s humid climate, relatively few jokotō have survived to the present day in good condition. Many ancient blades have rusted away entirely over the last millennium. However, a handful of remarkable archaeological discoveries – often in tombs or as preserved shrine treasures – have shed light on the form and craftsmanship of these early swords. Some of these finds are considered National Treasures of Japan due to their historical importance. This section highlights a few of the most significant examples and discusses their preservation status.
- Inariyama Sword (稲荷山古墳出土鉄剣) – Discovered in 1968 in the Inariyama burial mound in Saitama Prefecture, this iron sword was hailed as the “discovery of the century” for ancient Japanese history. X-ray analysis in 1978 revealed a long inscription inlaid in gold on the blade, totaling 115 Chinese characters. The text, which includes the date of a xīn-hài year (corresponding to 471 AD) and the genealogies of a warrior clan, has provided invaluable insight into 5th-century politics. It even names a great king “Wakatakiru,” believed to refer to Emperor Yūryaku. The Inariyama sword itself is a single-edged straight tachi about 73 cm long, heavily corroded but intact. Its blade was forged of imported steel (scientific examination of the rust indicated the metal came from ore in the Yangtze River region of China) and then adorned with gold inlay characters. Now stabilized and conserved, the sword is on display at the Saitama Prefectural Museum of the Sakitama Ancient Burial Mounds and is designated a National Treasure. The inscription remains faintly visible, with the contrast enhanced by lighting in the exhibit. This find underscores how a sword entombed in a sealed stone coffin for over 1,500 years could survive – albeit rusted – long enough for modern science to reveal its story.
- Eta-Funayama Sword (江田船山古墳鉄剣) – Excavated in 1873 from the Eta-Funayama Kofun in Kumamoto (Kyushu), this sword is another celebrated inscribed blade from the 5th century The Eta-Funayama sword is an iron tachi with a silver-inlaid inscription of about 75 Chinese characters on its blade. Though the inscription is partially obscured by corrosion, it has been interpreted to indicate that the sword was made during the reign of Emperor Yūryaku (the same Wakatakiru mentioned on the Inariyama sword). Notably, the text also records the name of the sword’s smith, Itaka, and the scribe Chōan who inscribed the blade – a rare glimpse into the craftsmen behind the weapon. This artifact was found alongside other rich grave goods, suggesting it was the prized possession of a powerful local ruler. Like the Inariyama example, the Eta-Funayama sword has been designated an archaeological National Treasure and is preserved at the Tokyo National Museum. Today, it is heavily rusted and fragmented in places, but museum conservation has halted further decay. Researchers used rubbings and X-ray imaging to decipher most of the inscription. The survival of this sword, buried in acidic soil for centuries, is remarkable – aided perhaps by the protective calcium carbonate layer from the burial environment and the silver inlay which resisted corrosion to some degree.
- Seven-Branched Sword (七支刀, Shichishitō) – Although not a tomb excavation, this sword deserves mention due to its antiquity and unique preservation. The Seven-Branched Sword was traditionally kept at Isonokami Shrine (Nara Prefecture) as a sacred heirloom and only re-discovered by scholars in the late 19th century. Likely forged in the 4th century, it measures 74.9 cm in length with a straight central blade from which six branch-like blades project (three on each side), giving it a distinctive forked silhouette An inscription in Chinese is inlaid in gold on its surface, stating that it was a gift from a Baekje king to a Japanese ruler, and possibly alluding to its ceremonial purpose. The Shichishitō was never used in battle – its brittle, mild steel material and unwieldy shape make that clear. Instead, it served as a symbol of interstate relations and divine protection. Uniquely, this sword has been conserved in near-original condition through continuous custody at the shrine. It was stored in a dry environment and handled as a sacred object, which spared it the fate of most iron artifacts. As a result, the Seven-Branched Sword today shows only surface rust, and its form is fully intact. It remains out of public view (a replica is displayed for visitors), but high-resolution images and studies have documented its metallurgical composition and inscription. The survival of this sword illustrates how controlled conditions and ritual safeguarding allowed an ancient iron blade to endure for over 1,600 years.
- A heavily corroded ancient iron sword from the 4th century, excavated from a kofun burial mound (Tōdaijiyama Kofun). Such swords often survive only in fragmentary condition due to long-term exposure to soil and moisture. Preservation efforts focus on stabilizing the rusted iron to prevent further decay.
Beyond these famous examples, archaeologists have unearthed numerous other sword fragments, hilt fittings, and related artifacts from Kofun and Asuka period sites. In the stone chambers of large tumuli, swords sometimes avoided complete oxidation, especially if they were placed in wooden coffins or alongside bronze mirrors (whose copper alloy might create a slightly protective micro-environment). Some smaller swords (tantō-like implements or iron knives) from the period have also been found in village or shrine contexts. However, completely intact jokotō blades are exceedingly rare. Each discovery, therefore, is significant in piecing together the technological and artistic attributes of the period’s weaponry. Modern conservation science, including careful desalination, consolidation of rust with tannic acid, and climate-controlled display cases, has enabled museums to preserve these relics for study. Through these efforts, the jokotō that have been recovered – though scarred by time – continue to inform and inspire, offering a tangible connection to Japan’s proto-samurai age.
Blade Styles and Characteristics of Jokotō
Ancient Japanese swords exhibit a variety of forms and construction styles that reflect their evolution and the influences of the time. Blade shape in the jokotō era was invariably straight (uncurved), but could be either double-edged or single-edged. The earliest swords introduced from the continent were double-edged ken (剣), suitable for thrusting. By the Kofun period, Japanese swordsmiths more commonly produced single-edged blades (tachi/直刀) which were optimized for slashing cuts. A key shift occurred by the mid-Kofun period (5th century), when swords transitioned from primarily stabbing weapons to cutting weapons, indicating a change in combat style and blade preference.
In terms of cross-sectional geometry, jokotō blades often employed shapes that later Japanese swords would rarely use. A prevalent form was hira-zukuri, a flat profile without a ridge, where the blade tapers in thickness from the spine to the edge in a smooth plane. Another was kiriha-zukuri, featuring a distinct angle (shoulder) where the upper part of the blade bevel meets the lower flat of the blade – a style also seen in some contemporary Chinese blades. These cross-sections lack the pronounced median ridge (shinogi) that became standard on later curved swords. The result is that many jokotō had broad, wedge-like blades with considerable weight, emphasizing cutting power. Blade lengths for jokotō varied; an average late Kofun tachi might have an edge length of 60–70 cm (about 2 shaku), which is slightly shorter than typical later samurai swords, though examples range from short dagger-sized pieces to very large ceremonial swords. Some rare specimens, likely ceremonial, reached extraordinary lengths (the Chokutō Kuro-urushi Tachi in Ibaraki, for instance, has a blade over 2.2 m long). Standard fighting swords, however, were sized for one-handed use on foot, often paired with a shield in battle depictions.
Another distinctive aspect of jokotō is the style of the hilt and pommel, which varied regionally. Many straight swords of the 4th–7th centuries featured ornate pommel designs inspired by Chinese and Inner Asian swords. Notable types of jokotō include:
- Kantō-tachi (環頭大刀) – A style distinguished by a ring-shaped pommel. The pommel ring (often cast in bronze) was sometimes shaped or decorated as a coiled dragon or phoenix. This design was directly inherited from Han and Six Dynasties Chinese swords and became popular in Japan’s early Kofun period. The ring served as both an aesthetic element and a point to loop a tassel. Many ring-pommel swords have been found in western Japan, indicating strong continental influence at the Yamato court.
- . The name literally means “deer-horn decorated sword.” Such swords were likely ceremonial or status symbols, as the elaborate antler-like fins would be impractical in close combat. This style appears to be unique to Japan and is thought to have ritual significance, possibly symbolizing martial prowess or tying the weapon to a clan emblem. Some tsurugi (double-edged swords) from the period also feature this motif, showing its broad use in elite contexts.
Different regions of Japan favored different sword styles. Archaeological evidence shows that sword-making centers had developed in areas like Yamato (Nara prefecture), San’in (Japan Sea coast), and Mutsu (northeastern Honshu) by the 6th century. These centers produced the above types in varying proportions. For instance, western Japan tombs often yield ring-pommel swords, while in Kyushu and the north, unique local types appear. One particularly interesting northern style is the Warabite-tō (蕨手刀). This type, associated with the independent Emishi tribes of the Tōhoku region, has an integral iron hilt that curves inward at the end, resembling the shape of a bracken fern fiddlehead (warabi) – hence its name. The blade of a warabite-tō is straight and single-edged, but the grip’s curvature and one-piece construction set it apart. Warabite swords were a regional adaptation of chokutō and remained in use even as central Japan moved to curved blades. In fact, it is hypothesized that an improved version of the warabite-tō provided the blueprint for the earliest curved sword (the kenukigata-tachi of the late 8th–9th century). This exemplifies how even within the jokotō period, there was significant diversity, and cross-pollination of designs eventually spurred innovation.
The mounting and furniture of jokotō also have defining characteristics. Unlike later swords which often have large, removable handguards (tsuba), most ancient swords had either minimal guards or fixed ones. Early blades might feature a small oval guard or no guard at all, with the hilt (tsuka) extending directly into a simple collar (habaki) and ferrule. Many chokutō hilts were made of wood and then wrapped or lacquered, but few survive; what we know comes from metal components that endured. The presence of loop mounts on scabbards indicates these swords were worn hung from a belt, edge down, secured by cords – the typical way of carrying a tachi in those days. Scabbards were wood, often lacquered, and sometimes fitted with bronze or iron chapes and throats for strength. Decorative sword fittings (collectively called koshirae) from the Kofun period show a penchant for elaborate design. Gold, silver, and copper inlay were used to embellish hilts and scabbards on high-status swords. Some pommels and guards were gilded or gem-studded. An excellent example is the set of ornate swords from the late 7th-century Shōsōin imperial repository, which have lacquered scabbards and gilded bronze pommels inlaid with glass – demonstrating that by the end of the jokotō period, sword mountings could be works of art in themselves.
The legendary Seven-Branched Sword (Shichishitō), a 4th-century iron sword with six protruding “branches” along its blade. The original artifact is preserved at Isonokami Shrine. This sword was a ceremonial gift from the Korean kingdom of Baekje to Japan, as indicated by its gold-inlaid inscription. Its unusual shape and rough surface (from centuries of oxidation) underscore its ceremonial nature; it was not used in combat.
The cutting edge of jokotō was usually straight without curvature, but some blades exhibit a very slight sori (curvature) as a result of differential cooling during quenching (a phenomenon later deliberately harnessed to create the curved katana). Visibly intentional curvature, however, did not appear until the very end of the ancient period. One transitional blade sometimes cited is the late-8th-century Kogarasu-maru, which is mostly straight but with a hint of curve and a double-edged tip – but this is already stepping into the next chapter of sword development. In general, a defining visual of an ancient Japanese sword is the austere simplicity: a straight profile, often with a rounded or spatulate tip (kissaki), plain iron fittings, and an absence of signature or maker’s mark (most jokotō are unsigned). Instead of signatures, the grandest blades “signed” themselves with their inscriptions on the blade.
Inscriptions and Ornamentation on Jokotō
One of the most fascinating aspects of some jokotō is the presence of inscriptions (mei) carved or inlaid into the blade. These inscriptions are among the earliest examples of writing in Japan and offer a rare written voice from a time when paper or wooden records have long vanished. In the absence of swordsmith signatures (which became common only in later periods), these long inscriptions serve a dual purpose: documenting the sword’s origin or intent, and adorning the blade with symbolic text. Typically executed in Chinese characters (the literacy of the day), the inscriptions were often rendered by chiseling the characters and then inlaying precious metals like gold or silver into the grooves – a technique known as zōgan. The result would have been glittering text running along the iron surface.
The content of jokotō inscriptions can be broadly grouped into two categories: dedicatory/auspicious messages and commemorative/personal messages. The former follows a tradition seen in China, where swords (or bronze mirrors) might bear invocations for divine protection or inscriptions of auspicious phrases and dates. For instance, a Chinese inscription might proclaim the sword was made in a certain cyclical year and carry a prayer for the wielder’s safety. This practice influenced Japan; however, Japanese craftsmen and patrons adapted inscriptions to include very specific local information. The inscriptions on the Inariyama and Eta-Funayama swords, as discussed, include personal names, familial lineages, titles, and references to a reigning monarch. Such content suggests these swords were made to honor the bearers and assert their loyalty and status. We can imagine that a regional lord who had a sword inscribed with his name and service to the great king was making a statement – both to the gods (as a sort of vow or record of deeds) and to posterity. In effect, these blades became inscribed steles in miniature.
Apart from text, some jokotō were also decorated with symbolic imagery and patterns. For example, the Eta-Funayama sword’s inlay includes small pictorial elements: historians noted tiny images of a fish, a bird, and a horse worked into the silver inscription, possibly representing auspicious omens or clan symbols. Such decorative flourishes indicate that the artisans were not only smiths but also skilled engravers. The act of embellishing a sword with noble metals also had practical benefit: gold and silver do not corrode like iron, so parts of these inscriptions have remained legible even as the surrounding iron rusted. Indeed, it was the slight contrast of remaining gold that first hinted at the Inariyama sword’s inscription before X-rays fully revealed it.
It’s important to note that not all jokotō bore elaborate inscriptions – in fact, most did not. The majority of utilitarian weapons from the period were plain. The highly decorated swords with inscriptions were likely reserved for kings, governors, or as shrine offerings. They stand at the apex of what was artistically achievable in that era. Other ornamentation on ancient swords included inlaid designs (such as arabesques or geometric motifs) on blades or hilts, openwork carving on sword guards, and metal pommel caps cast in the shape of animals or flowers. A bronze openwork pommel in the shape of a coiled dragon, for instance, might adorn a high-ranking officer’s sword, symbolizing valor.
As artifacts, inscribed jokotō have immense historiographical value. They have corroborated and clarified events mentioned in textual records. For example, the name Wakatakiru (Ōkimi) on both the Inariyama and Eta-Funayama swords provided tangible evidence of that ruler’s influence across distant provinces
. They also inform us about the use of Chinese writing in a Japanese context – the fact that Japanese names were phonetically rendered in Chinese characters (many used as syllabograms) on these swords shows the adaptation of writing to the Japanese language at that time. In short, every preserved inscription is a direct message from the 5th or 6th century, telling us who wielded the sword and why it mattered.
Conclusion
The jokotō of Japan’s ancient era are more than just primitive forerunners of the samurai katana – they are treasures that encapsulate a formative age of Japanese civilization. In their metal and form, they reflect the transmission of technology from continental Asia and the gradual refinement of Japan’s own metallurgical genius. In their inscriptions and adornments, they carry voices and artistry from an era that left few other written records. And in their ceremonial and grave contexts, they illuminate the beliefs and social structures of early Japanese society, where swords served as emblems of divine and temporal power.
Physically, jokotō swords present a straightforward silhouette: chokutō with shining straight blades meant to be wielded on foot, often with distinctive fittings like ring-shaped pommels. Yet within that straightforward form was the embryo of later innovations. By the end of the 8th century, swordsmiths experimenting with different heat treatments and regional styles would introduce a deliberate curvature to some blades, giving rise to the earliest curved tachi. Those developments mark the close of the jokotō chapter and the dawn of the kotō (old sword) period. It was a gradual evolution, not a sudden replacement – for a time, straight and curved swords coexisted. But as mounted warfare became prevalent in the Heian period, the curved sword proved superior for slashing from horseback, and the ancient straight sword designs faded from practical use.
Thus, the legacy of the jokotō lies in both what they gave and what they yielded to. They established the fundamental techniques of Japanese sword forging and the cultural reverence for the sword, and then they gracefully gave way to newer forms as the needs of the time changed. Today, the preserved jokotō in museums and shrines allow us to gaze back at the weapons that armed the kofun-building kings and the heroes of Japan’s earliest legends. In their silent, time-worn way, these swords tell the story of a nation in the making – a story forged in iron and written in gold. Each blade, whether a plain fighting sword or a gilded ritual piece, remains a tangible link to the ancient past, ensuring that the spirit of Japan’s earliest swords continues to be remembered and revered.