was a feudal domain under the Tokugawa shogunate of Edo period Japan, located in Harima Province in what is now the southern portion of modern-day Hyōgo Prefecture. It was centered around Akashi Castle, which is located in what is now the city of Akashi, Hyōgo. History At the start of the Edo period, the area around Akashi was part of the vast holdings of the Ikeda clan of Himeji Domain. In 1617, Ikeda Mitsumasa was transferred to Tottori Domain and his former estates were divided. Ogasawara Tadazane, the son-in-law of Matsudaira Nobuyasu received a 100,000 koku portion, which formed Akashi Domain, and he was ordered to construct a castle. Akashi Castle was located on a strategic location controlling the San'yōdō highway, which connected the Kinai region with western Japan and was also the main route north to Tanba and Tango Provinces. It was also located very near the coast of the Seto Inland Sea, overlooking the narrows to the island of Awaji island. Considered by the Tokugawa shogunate to be a backup to Himeji Castle, Akashi Castle was the final line to defend Kansai region against any attack from the west. The Ogasawara clan were transferred to Kokura Domain in 1632, and due to the strategic nature of the domain, it was reassigned only to trusted cadet branches of fudai daimyō clans: the Toda-Matsudaira, Okubo clan, Fujii-Matsudaira clan and the Honda clan. After Honda Masatoshi was demoted for poor governance in 1682, the domain was entrusted to a Shinpan clan: the Echizen-Matsudaira, formerly of Ono Domain, which retained it to the Meiji restoration. The 8th daimyō, Matsudaira Narikoto , was an adopted heir and was born the 25th son of Shogun Tokugawa Ienari. As an indication of his status, the domain was increased in kokudaka from 60,000 to 80,000 koku and was given administrative control over an additional 20,000 koku of tenryō lands. However, this was not enough to offset the vast outlay of funds which the domain had been forced to pay the shogunate for the "privilege" of having the son of a Shogun as heir, and the domain faced financial difficulties. In the Bakumatsu period, the domain was ordered by the shogunate to construct twelve artillery batteries for coastal defense, and also to provide troops to man the defenses of Edo at Shinagawa and along the coast of Sagami Province. The domain also provided troops for the First