In 1185, Japan’s Taira (Heike) and Minamoto (Genpei) clans played out the final battle of the Genpei War, the result of which would have a profound effect on Japan ushering in its first shogun with Kamakura as the shogunate.

In the latter part of the 12th century, the entire archipelago was in turmoil as the two clans asserted their power. The era saw violent rebellions by monks and the conflagrations of Todaiji and Kokufuji temples in Nara, two of Japan’s most important places of worship. War and famine spread. So dark and tumultuous were these times, that many Japanese people feared they had entered “mappo” — the end of the Buddhist Dharma, or the age of degeneration.

The final stand-off in the Genpei War took place in the Shimonoseki Strait between Honshu and Kyushu at Dannoura where the Seto Inland Sea spills out through the narrow channel into the Japan Sea.

The Heike clan was poised to win this naval battle, their main advantage being that they possessed more boats and manpower. But the Inland Sea is not to be underestimated. A living, breathing entity the sea quietly draws in water from the surrounding seas and expels it six hours later in what is known as the “changing of the tides.” Twice a day, like a sleeping sea dragon, the Inland Sea slowly inhales, then exhales. The surprise turning point of this sea battle was a result of the Minamoto’s cunning plan. Accomplished seafarers, they planned their attack so that when the dragon exhaled, the less experienced Heike would be carried out to sea.

At the height of the battle, with faultless prediction, the tide changed and the Heike found themselves sailing backward against a strong current, with only a small flotilla able to struggle against the tide and remain inside the strait. From there, they pushed forward to meet the enemy head on. But the Minamoto, with the tide to their advantage, overtook quickly, their archers picking off the Heike by the hundreds. The boats, tossed by the surging waters over the dragon’s tongue, finally clashed and the Minamoto boarded the Heike’s vessels after which swords, daggers and pugilist combat ensued. Realizing their fate, the remaining Heike forces attempted to save their honor by jumping into the drowning waters to perish.

So full of corpses was the Inland Sea, the briny waters turned sanguine. Dannoura was the last of such battles in the 450 kilometer long Inland Sea where scores of the dead washed up on the shores of small islands, a memory kept alive today in names such as Kitagi Island’s “Chi no Hama” (“Blood Beach”). The “Heike crab,” a type of crustacean that bears a countenance likened to a warrior’s, is believed to represent the fallen Heike at the bottom of the sea. In addition, actions were taken to assure repose of the Heike souls, a step deemed necessary to discourage them from coming back to avenge the people. Taira poems were included in the “Senzai Wakashu,” the seventh imperial collection of poetry, in the hope of pacifying the spirits. So famous is the battle at Dannoura that its rendition in the epic “Heike Monogatari” spawned a new niche of literature called “war tales.”

But perhaps one of the most enduring extant effort to appease the Heike souls is that which takes place on an Inland Sea island of just 460 people, located between Dannoura and Mizushima battle sites. The residents not only erected a temple to the defeated warriors, but for eight centuries they have danced for the repose of their souls. Steeped in this history and tradition, the Shiraishi Bon dance has been passed down from generation to generation and is taught from kindergarten. Twelve years of practice culminates in adults performing one of the most complicated Bon dances imaginable: a combination of 12 different ensembles, with 12 sets of costumes, all of which blend together into an extravaganza commanding the expertise of dozens of people. For more than 800 years, with the exception of the closing month of World War II, the dance has been performed annually, earning it the status of a national intangible cultural property of Japan. The current performance is a pared down version that includes only seven of the 12 segments, a measure taken to account for the ever-decreasing population of the island. During the four-day Bon festival in August, the livelihood of the dance depends on those who return to visit their hometowns, bringing back with them these artistic skills.

The islands of the Inland Sea and their traditions remain in crisis as Japan’s population declines, and island populations continue to vanish. The Shiraishi Elementary School closed in April due to a lack of students. Only the junior high school remains but it will close its doors in two more years.

While these changes are inevitable, it doesn’t stop me from wondering who will carry on the memories of the Heike, their fleeting lives expressed in the tender entwining movements of a golden fan held in the fingers of a dancing woman? Will the old grizzled men still salute the bravery of the Heike by wearing the folk costume while hoisting a straw hat high in the air? Will the adults forget how they, as children, wavered at their new dance steps while looking up into the night air, hands poised to frame the moon?

As the taiko drummer beats on, and the elder sings out the mournful song of the Heike, I wonder how much longer the Heike will hear them.

Amy Chavez is the author of “Amy’s Guide to Best Behavior in Japan: Do it Right and Be Polite!” (Stone Bridge Press).