Mitarai, on Osaki Shimojima in the Inland Sea grew into a major seaport in the mid 17th Century. Initially it was a good spot for boats to wait for favorable winds and tides, but prospered by offering services that the sailors desired.
The Sumiyoshi Shrine on the waterfront dates from this time.
Sumiyoshi shrines are noted for offering protection for those undertaking sea journeys. The original Sumiyoshi shrine is in Hakata which was the main point of embarkation for mainland Asia. The Sumiyoshi shrine established in what is now Osaka, the main port serving the capitals of Yamato, is now considered the head shrine.
The three main kami are the Sumiyoshi "brothers", Sokotsutsuno, Nakatsutsuno, & Uwatsutsuno, who according the the standard mythology were created when Izanagi purified himself after visiting Izanami in Yomi. It is possible they represent the three main starts of the Orion Constellation which were used for navigation. Later Empress Jingu was added,.