On the Existence of Naval Forces in the Heian Period

There is an opinion that the national naval forces in the Heian periodhave retreated, compared to the previous period, and the naval forces ofancient Japan are considered to be different from the pirates of medievalJapan, and not to be full-scale naval forces. In this study, ‘naval forces’ isdefined as the military organizations which is separated from the army,using military ships. This study is to find out the existence of naval forcesin the Heian period, and to make their characteristics clear by comparingthem with those of the pervious era. First, we examined the activities of naval forces in Fujiwara no Sumitomorebellion. In Sumitomo’s rebellion, government forces fought against thepirates. Therefore, battles usually took place on the sea or on the coast. Butmost of the battles were described as occurred on land. In battles usingships, combatants on land boarded the ships, which were controlled by theseamen, hijacking enemy ships or putting them out of action. These forceswere basically combatants operating on land, not a naval-specific group. Compared to the previous period, the foreign expeditionary forces of 7thcentury were called funaikusa(forces of vessels), and persons from the clanwith naval capabilities were appointed commanders of foreign expeditionary forces. Meanwhile, in the expeditionary forces to invade Silla, which wereplanned in the 8th century, commanders did not have a connection with thenaval forces. The national military forces were ostensibly based on landforces, putting defense above foreign expedition, so that there were somechanges in the ancient naval forces. Vessels of the naval forces wereoriginally used for transportation during peacetime, converted into warships. Coastal defense in response to external threats was only made in a way ofpreventing enemies from landing, and there was no institutional distinctionof giving the name of “naval forces” to the military group in charge of suchpassive security. At the end of the Heian period, the warriors on the seaemerged, and in the Middle Ages of Japan, the naval organization thatmobilized those warriors at the national level began to form a full-fledgednaval force.