Their existence dates back to the early 3rd – 7th centuries, when their extensive knowledge of navigation between waters made them the naval force of Yamato Japan in Kyushu.

Their knowledge and ability to use tidal changes, weather patterns and star constellations ensured their successful routing and voyaging on the sea during their regular exploration.

[2] Their ability to navigate the seas, especially at night, made them useful to the Japanese imperial government during the 3rd to early 5th centuries and they were effectively the naval force of Yamato Japan.

[6] Before voyaging, the Azumi people often performed rituals of sea-worship to the oceanic deities as they believed this assisted them to establish control and territory in various regions of the sea.

During these times, even though they were no longer seafarers, it is believed that they still maintained their intrinsic connection to their past ancestors through regularly praying to the deity Isora, thankful for the water which flowed from Kamikochi's mountains granting them successful crop irrigation.

Emperor Tenumu invaded South Kyushu, but instead of inflicting war on the Yamato Court, they offered tokens of their gratitude in appreciation of the Azumi people's comradery and supposed obedience to them.

[2] The spirit of Isora is represented as a seahorse,[14] and is considered a symbol of purity, providing spiritual guidance to the Azumi people throughout their day-to-day life.

[2] Additionally, Azumi no Isora is suggested to be the primordial human ancestor as it was him that first performed the dance ritual known as “Sei-no-no” (also known as Seino and Kuwashi-O).

There is one in Genkai Bay on Shikanoshima Island dedicated to Azumi no Isora which contains sacred stones to represent the sea turtles, as well as over a thousand deer antlers to maintain their relationship with the deities.

It was believed to result from her disobedience in following the Japanese social construct of a woman – she initiated the sexual intercourse, a role assumed to be dominated by men.

[16] Although they eventually achieve success with their creation – birthing the Eight Islands of Japan and creating kami – their attempts lead to other unfortunate events, including the death of Izanami.

The Azumi generations detail the creation story of Isora and how his once hidden jewels located in a dragon palace on the seafloor were said to control the tides and weather patterns.

They believed that the king dragon which resided in the palace did not show himself due to his ugly outward appearance; his body covered with abalone, barnacles and shellfish.

However, it is suggested that the ‘kagura’ dance possessed the ability to lure out the dragon, leading the Azumi people to his endless supply of ‘treasure’: divine knowledge of the sea.

In the city, there is a traditional spot in which all three rivers (Azusa, Karasu and Nakabusa), as well as the water from the melted snow of Kamikochi's mountains, meet.

[8] During this celebration, the Azumi People commemorate their direct connection to water and their gratitude for it as it has always assisted them – both in their history as skillful seafarers and crop farmers.

The shrine is presided over by a priest descended from the Azumi clan, and its biennial gojinkosai ceremony is designated an intangible cultural property by the prefecture.