Aoshima Sea-Fortune Mountain-Fortune Legend

The Aoshima Sea-Fortune Mountain-Fortune Legend is a narrative cycle from the Hyūga coast, telling of two brothers: Hoteri-no-Mikoto (Umisachi-Hiko, 'Sea-Fortune'), and Hoori-no-Mikoto (Yamasachi-Hiko, 'Mountain-Fortune'). Both were sons of Ninigi-no-Mikoto and Konohana-no-Sakuya-Bime-no-Mikoto. When Yamasachi-Hiko loses a fishing hook borrowed from his elder brother, the deity Shiozuchi-no-Kami guides him to the palace of Watatsumi, the ocean deity. There he marries Toyotama-Bime-no-Mikoto, the ocean deity's daughter. After three years, he returns to the terrestrial realm bearing the recovered hook and two sacred jewels—the Tide-Rising Jewel and the Tide-Falling Jewel—with which he subdues his brother and establishes the Hayato as his descendants. Later, Toyotama-Bime arrives on land to give birth but, after the birth-hut taboo is violated, departs for the sea.

The narrative unfolds in three movements: the loss of the hook and journey to the ocean palace; marriage to the ocean deity's daughter and receipt of sacred treasures; and the subjugation of the elder brother through tidal power, establishing Hayato allegiance. The tension between mountain and sea, the conferral of authority through sacred objects, and the violation of birth-hut taboo form the central motifs of Hyūga mythology. Yamasachi-Hiko, as grandfather of Emperor Jinmu, anchors the mythological prelude to the imperial genealogy.

The primary site is Aoshima Shrine in Aoshima, Miyazaki City, traditionally identified as where Yamasachi-Hiko returned from the ocean palace. The shrine's principal enshrined kami (shusaijin) are Hikohohodemine-no-Mikoto (Yamasachi-Hiko), Toyotama-Bime-no-Mikoto, and Shiozutsu-no-Okami. The nearby rock formations known as the "Ogre's Wash-Board" (*oni no sentakuita*) evoke the seascape of Watatsumi's realm. Related sites scatter across the Hyūga coastal region; Udo Grand Shrine (Nichinan City) preserves the birth-hut legend, while Miyazaki Shrine enshrines Emperor Jinmu. These form a unified Hyūga mythological zone.

Core accounts appear in the *Kojiki* (Records of Ancient Matters, 712 CE), fascicule on Hoori-no-Mikoto and Toyotama-Bime; the *Nihon Shoki* (Chronicles of Japan, 720 CE), Section 10 of the Divine Age, Book 1; and fragments of the *Hyūga Fudoki* (Hyūga regional gazetteer, 8th c.). The Aoshima Shrine founding history and early modern gazetteers such as the *Hyūga Chishi* (1884) document regional establishment. Modern mythological studies draw on Orikuchi Shinobu's *Ancient Studies* and recent *Kojiki*/*Nihon Shoki* scholarship.