This paper estimated route of the Japanese Inland Sea, Setonaikai, from the contents written in Manyo-shu, old poetry collection in Japan. In the 15th volume of Man-yo-shu, many waka poems, traditional Japanese poems, were written by the mission sent to Silla Kingdom in 736 AD. I extracted place names from waka poems in that and deduced the route in Nara Period from the perspective of route theory and coastal navigation. As a result, I drew the Setonaikai route in the Nara period in Figure 5.
Man-you-shu
coastal route in Setonaikai
in Nara period