Takaoka Jinja, which I visited in July 2010, is the second of the ex post facto shrine reports I compiled while under self-isolation during the Covid-19 State of Emergency in Tōkyō. Note that it is now a kenmusha of the nearby Aga Jinja (英賀神社).
It is one of the four shrines listed in the Harima Province/Shikama (播磨国/餝磨郡) section of the Engi Shiki. In 782, Sakanoue no Tamuramaro (坂上田村), who was appointed as Shōgun by the Emperor Kanmu, and had been tasked with subduing the Emishi people in what is now Tōhoku in the north of the country, visited the shrine to pray for a successful campaign. In 826 the shrine was moved to its current location. In 1243 Hōjō Tsunetoki, the fourth regent of the Kamakura Shōgunate, had a retainer present a package of silver coins and a long sword to the shrine and had a rain inducing ceremony (Kiu-sai, 祈雨祭) held there.
The military governors of Harima Province, the Akamatsu Clan, and the lords of Himeji Castle, the Matsudaira Clan, were also devotees of the shrine, building and repairing the shrine buildings and making donations, among other things. In 1912 the shrine was designated a Shinsen-heihakuryō-kyōshin-jinja and 20 years later became a Prefectural Shrine.
Emperor Ōjin 応神天王
Emperor Chūai 仲哀天王
Emperor Sudō 崇道天王
Kotoshiro-nushi-no-mikoto (90) 事代主命
Sumiyoshi Ōkami 住吉大神
Prince Iyo-Shinnō 伊豫親王
Empress Kōmyō 光明皇后
From Merged Shrines
Inari Jinja 稲荷神社
Annual Festival: October 10
Looking at the shrine’s kami, the originally enshrined ones were the five beginning with Emperor Ōjin; the three beginning with Sumiyoshi Ōkami came next, and the three beginning with Uga-no-Mitama were added in the Meiji Period. Note that Emperor Sudō does not appear in the official list of emperors. In life he was Prince Sawara (早良親王, 750-785), the fifth son of the 49th emperor, Kōnin (光仁天皇, 709-782); in 781 the latter abdicated in favour of his son, Yamabe, who became Emperor Kanmu, and named his younger brother Sawara as crown prince. Political problems followed, however, and after being exiled from the capital Sawara died, possibly of self-induced starvation. After his death he was given the title Emperor Sudō. I think this is the only example of someone being named emperor posthumously. Prince Iyo-Shinnō was one of Emperor Kanmu’s 36 children and hence a nephew of Prince Sawara, and, like his uncle before him, met an untimely death. His mother was Fujiwara Yoshiko (藤原 吉子), and having got caught up in intra-Fujiwara clan machinations mother and son were accused of treason and allowed to commit suicide in December 807.
In the grounds of the shrine there are many large rocks, perhaps the most notable of which is the one directly behind the main hall (unfortunately I either failed to take, or have since inadvertently deleted, a photo of it: there is such a photo on the shrine’s home page). It is considered sacred and is known as the Kamagura (clam, 蛤) Rock. The name derives from a local inhabitant once having picked up a clam from the top of the rock, thus gaining happiness, prosperity, and a long life (福徳長寿)