* Image is for illustrative purposes only.Yayoi and Kofun Periods
弥生・古墳時代
The primordial stage before the emergence of the Japanese sword. Iron straight swords transmitted from the continent—China and the Korean Peninsula—became established in the Japanese islands, accumulating metallurgical techniques and laying the foundation for sword culture. Iron swords and blades interred in ancient burial mounds (kofun) serve as precious witnesses to this era's sword history.
Description
Iron Tool Transmission and Establishment
From the middle Yayoi period (around the first century BCE), continental iron goods began to flow into the Japanese islands via the Korean Peninsula. The earliest iron tools were primarily agricultural implements and work tools rather than weapons, but by the late Yayoi period (around the third century), iron swords, spears, and small blades (*tōshi*) began to appear as burial goods. These iron items were initially imports, manufactured in workshops in southern Korea (the Gaya and Three Kingdoms regions), and domestic mining and refining of iron sand and iron ore had not yet begun in earnest during this era.
Establishment of Iron Smelting Technology in the Kofun Period
With the onset of the Kofun period (late third to seventh century), iron smelting technology was formally introduced to the Japanese islands by immigrant technicians from the Korean Peninsula, particularly skilled groups from Baekje and Gaya. Furnaces that would become the prototype of *tatara* smelting were established in the Chugoku region (present-day Shimane, Tottori, and Okayama) and the Kinai region, and techniques for direct iron reduction from iron sand began to take hold. Iron sand from the Izumo region was of exceptional quality, establishing the foundation for what would later become renowned as "Izumo iron sand"—a premier smelting region.
Types and Characteristics of Burial Swords
Iron swords and blades interred in kofun are classified into diverse types: the *kantō-tachi* (ring-pommel sword), single-phoenix ring-pommel variants, double-dragon ring-pommel variants, and the *kei-tō tachi* (pointed-pommel sword). These large swords were heavily influenced by Han and Six Dynasties Chinese culture, with most featuring ring-shaped decorative elements on the pommel (*tsukagashira*). The blade was fundamentally straight-edged, without the curved form that would define later Japanese swords, with cutting points tapering to an acute angle in an upswept form. Iron quality remained uneven, and the sophisticated layered forging (combining core and skin iron) that characterizes later Japanese swords has not been confirmed in these examples, though some superior specimens show traces of heat treatment (*yaki'ire*) on the blade.
Political Significance of Burial Swords
Swords and blades interred in kofun were not mere weapons but prestige goods symbolizing the authority and status of the deceased. The Yamato realm distributed iron swords to powerful regional chieftains, thereby forming and reinforcing networks of political control. The *Shichishi-tachi* (Seven-Branched Sword)—a seven-pronged iron sword now preserved at Ishikami Shrine—is renowned as a diplomatic gift sent by Baekje to the Yamato ruler, vividly demonstrating the continental diplomatic relations and the political function of swords in this era. The silver-inlaid inscribed large sword excavated from the Eda Funayama kofun in Kumamoto Prefecture (bearing the inscription "Ruler of All Under Heaven [...]") is also an important artifact from this period.
Positioning as Prehistory of the Japanese Sword
The straight swords of the Yayoi and Kofun periods lacked the three defining characteristics of the Japanese sword: curved blades, layered forging (combining skin and core iron), and tempered edge-patterning (*hamon*). However, the iron smelting and sword manufacturing techniques accumulated during this era, together with the cultural and political positioning of swords, became the foundation for the birth of the Japanese sword from the Heian period onward. The refining techniques for *wa-tetsu* (Japanese iron), the precursor to *tamahagane*, were developed and perfected, and the spiritual and symbolic culture embedded in swords took shape during this long prehistoric age. For collectors, artifacts from this period represent an archaeological touchstone for understanding the deep roots of Japanese sword culture.
Characteristics of This Era
- All blades were straight-edged, lacking the characteristic curve (sori). They developed under the direct influence of the straight-sword cultures of continental China and the Korean Peninsula; the distinctive curve that would later define Japanese swords did not yet exist.
- The *kantō-tachi* (ring-pommel sword), featuring ring-shaped decoration on the pommel (*tsukagashira*), is the representative type. Diverse designs—single-phoenix, double-dragon, three-leaf—were applied, reflecting the aesthetic sensibilities of continental Six Dynasties culture.
- Ironworking was led by immigrant technicians, with the prototype of *tatara* smelting developing primarily in the Izumo and Kinai regions. This era marked the beginning of *wa-tetsu* (Japanese iron) production through magnetite reduction—a crucial developmental period.
- Burial swords and blades served as prestige goods indicating the deceased's political status and authority. The Yamato realm distributed swords to regional chieftains, thereby forming networks of political control.
- Layered forging (combining skin and core iron structures) had not yet developed, and iron quality remained inconsistent. However, some superior examples show traces of heat treatment (*yaki'ire*).
- Swords functioned as diplomatic gifts exchanged with the continent during this era. The *Shichishi-tachi* preserved at Ishikami Shrine—a gift from Baekje to the Yamato ruler—exemplifies this diplomatic role.