The Inland Sea Lane

In the latter half of the Age of Provincial Wars, Murakami Clan gained power with their bases on Geiyo Archipelago in the middle of West Inland Sea Area. Murakami Clan is composed of 3 sub-clans; Nojima Murakami, Kurushima Murakami, and In’noshima Murakami. They used to be called Santo Murakami (Three-Islands Murakami) or Santo Murakami Navy. Here, I sometimes call Nojima Murakami, the head sub-clan of the three, just Murakami. Murakami Clan was subordinate to Kono Clan, the Guardian of Iyo, and established a good relationship with Mori Clan. The Clan extended their power over East Inland Sea Area, and assumed control of Shiwaku Islands in Sanuki, Hitsuishi-jima Island and Yo-shima Island in today’s Sakaide City, Hon-jima Island, Ushi-jima Island, and Hiro-shima Island in today’s Marugame City, Takami-shima-Island and Sanagi-shima Island in today’s Tadotsu Town, and etc. all in today’s Kanagawa Prefecture. Shiwaku Islands were located in the center of Bisan Archipelago between the Sea of Harima-nada and the Sea of Hiuchi-nada. They attracted many ships and boats, and provided boatmen to transport travelers and goods. Murakami Clan came to control Shiwaku people, and became a master who organized and controlled local territorial pirates at difficult straits in Inland Sea. Against Murakami Clan’s extending its power, Oda Nobunaga guaranteed Shiwaku ships’ shipping to Sakai in the document by Shwaku Guardhouse dated March 26, 1577, the seventh year of Tensho. The document shows Shiwaku Islands were placed under the influence of Oda Nobunaga. Until around 1584, the 12th year of Tensho, however, Murakami Clan committed themselves to the islands. The islands seem to have been under the influence of the both sides actually. The Inland Sea has The Sea of Harima-nada, Bisan Archipelago, the Sea of Hiuchi-nada, Geiyo Archipelago, the Sea of Itsuki-nada, Boyo Archipelago, the Sea of Iyo-nada, and the Sea of Suo-nada from east to west. It has “nada” (a rough sea with strong winds and waves, and with rapid currents, where sailing is difficult) and archipelagos alternately. Between nada, there are straits with big ranges of tides. The islands near those straits were located with important ports, and with sea castles of pirates as well. Nojima Castle, Nojima Murakai Clan’s main castle and stronghold, for example, controlled Hanaguri Strait, Kojin Strait, Funaori Sterait. Those are rapid straits with 10-not (about 19 km/h) currents whirling at fastest. Kurushima Strait has as rapid as 12-not current at the rising tide, which causes famous Hachiman-uzu, or Hachiman Vortex. Ships needed local pilots, and were easily captured from Kurushima Castle, Kurushima Murakai Clan’s main castle and stronghold. These two areas have many marine accidents even today, and are known as dangerous sea areas with poor views, with narrow widths to sail, and with rapid currents. Inland Sea Lane used to be thought to have started during Edo Period, but, today, it can date back to before the Age of Provincial Wars. The lane used to have 2 coastal routes and 3 offshore routes. Aki coastal route sailed along Sanyo coast, and Iyo coastal route along Shikoku coast. The offshore routes sailed from the west through the Sea of Itsuki-nada, Hanaguri Strait, Yuge Strait, and the Sea of Bingo-nada; through The Sea of Itsuki-nada, Funaori Strait, Miyako Strait, the Sea of Hiuchi-nada, and the Sea of Bingo-nada; through the Sea of Itsuki-nada, Kurushima Strait, and the Sea of Bingo-nada.