The Water Transportation in the Kanto Plain and the "Piracy" there (1)

      The Satomi Clan can be considered the easternmost clan that had sea forces.  The clan used to be based in the Boso Peninsula.  The north-easternmost tip of the peninsula is Cape Inubo.  The Black Japan Current, which runs along the Japanese Archipelago from the south, departs the islands east toward U.S.A. off the cape, where the Kurile Current, which runs from the north, meets the Black Japan Current.  Navigation methods and needed skills might have been quite different beyond the junction of the two sea currents.  As you have seen, Kumano Pirates sometimes exported some of their human resources and affected other sea people in other parts of Japan.  But Cape Inubo was the dividing line for them.

     Just to the north of Cape Inubo, there used to be an orifice of a big inland sea, Katori Sea.  On the peninsula between Katori Sea and the Pacific Ocean, Kashima Shrine was located.  On the southern coast of Katori Sea, there stood Katori Shrine.

     Kashima Shrine was officially considered and actually worked as the gateway for the ancient Yamato central government to intrude into the north-eastern part of Japan, which would be later called Mutsu Province, or to subdue and rule Emishi, who were not subject to the imperial central government yet.

     Katori Shrine used to be the gateway to the Kanto Plain, and governed the water transportation on Katori Sea.  Hasetsukabe Atahiohohiro of Inba County, Shimousa Province, expressed Katori Sea in his tanka poem included in The Ten Thousand Leaves, the oldest collection of Japanese poetry, “A wave suddenly washed over a bow. The draft unexpectedly fell over me.”  After the poem, he had to go far away to Kyushu as “sakimori” to defend Japan.