The Toi Invasion (1019) and the Nihontō — Tachi of the Northern Kyushu Warrior Bands Who Repelled the Jurchen Assault

What Were the Toi? — The Northern Kyushu Assault of Kannin 3

From the 3rd to the 4th month of Kannin 3 (1019), an armed force that Japanese sources call "Toi" descended upon Tsushima, Iki, and the coastal shores of Hakata Bay in Chikuzen. The Toi are believed to have been a Jurchen group; a contingent of a force that had been ravaging the eastern coast of the Korean Peninsula at the time organized a fleet of several tens of vessels and advanced along the Japanese coast. Contemporary aristocratic records, including the diary Shōyūki by Fujiwara no Sanesuke, document that on Tsushima and Iki many islanders were killed or abducted and houses and fields were burned. For the aristocratic society of the Heian capital, this incident, while a distant event in Kyushu, was also conveyed to the capital with the shock of an armed force landing directly from across the sea. Among scholars there remains debate about exactly which group the Toi refers to, but the widely shared view is that they were a maritime force that operated along the Northeast Asian coast at the time.

Course of Events

The sequence of events from the Toi assault to their repulsion is generally understood to have proceeded in roughly the following order.

• Attack on Tsushima and Iki and the damage inflicted
• Attempted landing on the shores of Hakata Bay (Chikuzen Province)
• Emergency mobilization of local warrior bands by the Dazaifu side
• Combat along the shores of Hakata Bay and the repulsion of the Toi fleet
• Pursuit of the retreating fleet and mopping-up operations by the Goryeo navy

A defining feature of this incident is that, because events unfolded so rapidly, the situation was resolved by local military force before a regular punitive army could arrive from the capital. It is said that by the time the urgent report reached the Heian capital, fighting along the shores of Hakata Bay had already been decided, and it is thought that the central government grasped the full picture of the situation only after the incident had largely been brought under control.

Fujiwara no Takaie and the Dazaifu Defense System

The person overseeing the practical affairs of Dazaifu at the time was Fujiwara no Takaie. Although a member of the regent family, Takaie had been posted to the region as Dazai no Gon no Sochi, and upon receiving the urgent report of the Toi attack, he mobilized the warriors and gunji class within the Dazaifu jurisdiction and had them defend the shores of Hakata Bay. Another defining feature of this battle is that it was not a regular army dispatched from the center but the private military force of local warrior bands and powerful local families that was organized to meet the enemy. The Dazaifu force engaged the Toi landing force along the shores of Hakata Bay and ultimately succeeded in repelling them.

Records show that after the fighting, debate arose at court over the rewards to be granted to the warriors who had mounted the defense. Because combat had been carried out after Takaie ordered the mobilization of local military force on his own judgment — before an official kanpu (a court order for military deployment) had been issued — the procedural question of whether the normal framework for assessing merits and granting rewards could apply was raised in aristocratic circles. It is said that in the end the conferment of court ranks and honors on those who had taken part in the defense was carried out, but this entire exchange is an interesting example illustrating how the relationship between the exercise of military force in the provinces and control from the center was understood in the middle Heian period.

Tachi and Bows That Sustained the Warrior Bands

The main force in this battle consisted of the private soldiers led by gunji and powerful local families within the Dazaifu jurisdiction — armed groups that were the prototype of the later warrior bands. Descriptions of weapons that appear in the sources suggest the use of bows and arrows in long-range combat and tachi in close combat. In this period of the Heian era, the transition from straight swords to curved tachi was still in progress, and the swords used in actual combat are thought to have been tachi of an archaic form with small sori, different in shape from the nihontō as it is imagined today. The Toi invasion stands as one of the early examples of local warriors fighting in an organized fashion with their own weapons and achieving results.

Historical Significance in Sword History and the Limits of the Sources

Although the Toi invasion itself was suppressed in a short time, its historical significance is not small. The fact that national defense was accomplished not by a regular army from the center but by the actual military power of local warrior bands overlaps with the trend by which the warrior class came to strengthen its political voice from the middle Heian period onward. It is said that aristocratic society, including Fujiwara no Takaie, also came to reaffirm through this incident the usefulness of provincial military force. From the perspective of sword history, tachi of this period combined the character of ritual prestige objects with that of practical weapons, and combat records such as those of the Toi invasion serve as one piece of evidence corroborating that the tachi of the Heian period were not mere ornamental objects.

On the other hand, records concerning the Toi invasion are centered on aristocratic diaries and official records such as the Shōyūki and the Nihon Kiryaku, and no sources survive that allow specific identification of the mei or makers of the tachi actually used in the fighting. The full extent of the damage inflicted on Tsushima and Iki at the time and the precise troop strength of the Dazaifu force are also subject to various theories, and it is difficult to state definitive figures. When discussing the Toi invasion in the context of sword history, it is more appropriate to view it not by tracing the provenance of individual swords but as a broader picture of the era — one depicting how middle Heian warrior bands equipped themselves for actual combat. The Toi invasion is often compared with the Genkō some two and a half centuries later, but it differs greatly in character from the Genkō in that it was not a regular national defense mobilization but was centered on local provincial military force, and it occupies a unique position in thinking about the actual nature of Heian-period warriors. The fact that Kyushu, by virtue of its geographic location, was a land directly susceptible to the influence of developments on the continent and the Korean Peninsula is also an aspect of the background to this incident, occurring as it did in northern Kyushu, that cannot be overlooked. Part of the reason why Dazaifu continued to fulfill its own unique role in both diplomacy and defense throughout the Heian period can also be sought in the accumulation of practical experience in coastal defense of this kind.