Tracing the Origins of the Japanese Sword: Blade Culture and Continental Metalwork in the Jomon and Yayoi Periods

Stone and Bone Ages to Metal — The Dawn of Japanese Sword Culture in the Archipelago

When modern people hear "Japanese sword," they envision blades of exquisite beauty, curved and forged from refined tamahagane. Yet this refined form is merely a flower blooming at the end of a long history. Tracing its roots leads us to the soil of prehistoric times — the Jomon and Yayoi periods.

During the Jomon period (approximately 14,000 years ago to around the 3rd century BCE), people used stone arrowheads and stone knives made by striking obsidian and slate as weapons and hunting tools. Obsidian from Hokkaido and the Wada Pass in Nagano was transported far to Kyushu through trade routes, demonstrating that the archipelago's society was far from isolated. However, metal technology — namely bronze and iron — was not developed by the Jomon people themselves. It was foreign knowledge that arrived from the continent across the sea.

The Impact from the Continent — The Arrival of Bronze and Iron Swords

The dawn of the Yayoi period marked the arrival of revolutionary metal technology alongside wet-rice agriculture, transmitted from the Korean peninsula. Recent radiocarbon dating suggests the Yayoi period may have begun as far back as the 10th century BCE (according to the National Museum of Japanese History's revised chronology), but metal tools are believed to have become widely distributed from around the 4th-3rd century BCE.

The first weapons to appear in the archipelago were made of bronze. Yayoi sites in northern Kyushu have yielded "saiguei doukken" (narrow-form bronze swords), matching those from the Mumun pottery culture of southern Korea. These double-edged swords, approximately 30-40 centimeters long, follow the lineage of Chinese Liaoning-style bronze swords. While evidence suggests they served as practical slashing weapons, noteworthy is that many examples are discovered either with blades worn down from use or completely unused.

Iron swords arrived somewhat later, with their spread beginning in northern Kyushu during the middle Yayoi period (around 1st-2nd century BCE). Iron produced harder and sharper blades than bronze, making it vastly superior as a practical weapon. Yet iron tools too carried meaning beyond mere implements.

Were Bronze Swords and Spears "Weapons"? — Their Transformation into Ritual Objects

In discussing the Yayoi period, the three types of bronze ceremonial vessels — doukken (bronze swords), douhouko (bronze spears), and doutak (bronze bells) — are indispensable.

Among these, perhaps the most dramatic archaeological discovery is the Aragamiyatani site, excavated in 1984 in Nita County, Shimane Prefecture (now Unnan City). From the slope of a small hill, 358 bronze swords emerged in orderly arrangement. This extraordinary number comprises about half of all Yayoi bronze swords discovered nationwide, and the same site yielded 16 bronze spears and 6 bronze bells.

None of these Aragamiyatani bronzes show traces of actual combat use; they were intentionally buried in the earth. Many bronze swords are of the so-called "ritual type" — lacking not only a hamon but even a blade itself. The Yayoi people had redefined bronze swords, originally transmitted as weapons, as "offerings to the gods" or "sacred objects in which divine spirits dwell."

Similar transformation appears in bronze spears. In northern Kyushu, practical "narrow-form bronze spears" evolved into "broad-form bronze spears" that became too large for actual use. Some exceed one meter in length, clearly transcending their function as weapons. These were symbols of authority and ritual implements used to visualize the "power" of chiefs.

What the Aragamiyatani and Kamoisaranoura Sites Tell Us — The Spiritual World of "Burial"

At the Kamoisaranoura site, located about 3.4 kilometers in a straight line from Aragamiyatani, 39 bronze bells were unearthed in a single discovery in 1996. This represents the largest number of bronze bells found nationwide. There remains no consensus on why such a concentration of bronze vessels was buried in the Izumo region (present-day Shimane Prefecture).

The act of "burial" itself reflects the religious worldview of the Yayoi people. Returning bronze vessels to the earth can be understood as a ritual to seal their spiritual power in the ground or to offer it to underground deities. In an agricultural society, the cycles of fertility and death-rebirth were closely intertwined, and burying bladed implements — tools that inherently take life — into the earth may paradoxically have been seen as an act of pouring life force back into the ground.

This "connection between blades and spiritual power" took deep root in later Japanese culture. The tachi in Heian period ceremonies, votive swords dedicated to shrines, and the Kusanagi no Tsurugi (Grass-Cutting Sword) — one of the Three Imperial Regalia — all stand in direct continuity with the Yayoi concept that "blades are sacred."

The Arrival of the Iron Age and the Deepening of Metal-Working Techniques

From the late Yayoi period into the early Kofun period (3rd-4th centuries), iron rapidly surpassed bronze. Iron became the dominant material in all fields — agricultural tools, implements, and weapons — and kanji (blacksmithing) techniques developed throughout the archipelago.

Early iron swords were chokutou (straight swords), their form strongly influenced by the continent. An iron sword excavated from the Inariiyama Kofun in Gyoda, Saitama (late 5th century) bears an inscription of 115 characters in gold-inlay, serving as precious evidence of the political system and reverence for swords of that era. Similarly, a tachi from the Edafunayama Kofun in Tamana County, Kumamoto bears a silver-inlay inscription, reflecting connections with the Yamato polity.

The "straight swords" of this period were not yet Japanese swords. However, the spiritual culture that regarded the blade as more than mere tool — as something bearing a name, imbued with spiritual power, and symbolizing master-servant relationships — was already firmly established.

The Path to Japanese Sword Birth — What Was Inherited from Prehistoric Times

The curved sword blade with "sori" (curvature) characteristic of the Japanese sword emerged in the middle Heian period (9th-10th centuries). Born as a curved blade suited to cavalry combat, its subsequent technological refinement gave rise to a cutting-edge blade culture without parallel in the world.

However, the spiritual foundation of the sword-smith's profession — the ritual manufacturing process of praying to gods, purifying body and mind, and forging steel in a sacred furnace — has roots in a far deeper place. A long spiritual lineage connecting back to when Yayoi people offered bronze swords to the earth and showed reverence and awe toward their spiritual power flows through the depths of Japanese sword culture.

The ancestors of the Jomon and Yayoi eras never thought "let us make Japanese swords." Rather, they encountered metal, this unknown force, sacralized it, and incorporated it into their social order and cosmic worldview. The accumulation of these endeavors, through thousands of years, crystallized into what is called the most beautiful blade in the world — the Japanese sword. Even in 2026, by visiting museums and archaeological sites, we can feel the continuity of this long history in our very being.