is a city in Hyōgo Prefecture, Japan. , the city had an estimated population of 28,208 in 13143 households and a population density of 310 persons per km². The total area of the city is . Geography Aioi is located in southwestern Hyōgo Prefecture extending largely south to north. The city's northern region is mountainous, the southern region faces the Seto Inland Sea.The area around the urban center, with Mt. Minosan in the north, Mt. Tengadai in the east, and Mt. Miya in the west, is a basin surrounded by small mountains. Neighboring Municipalities Hyōgo Prefecture Tatsuno Akō Climate Aioi has a Humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall. The average annual temperature in Aioi is 15.0 °C. The average annual rainfall is 1519 mm with September as the wettest month. The temperatures are highest on average in August, at around 26.0 °C, and lowest in January, at around 4.6 °C. Demographics Per Japanese census data, the population of Aioi has remained relatively constant over the past 70 years. History The Aioi area was part of ancient Harima Province and was located on the San'yō highway linking western Japan with the Kinai region. The area was the location of a stronghold of the Ebina clan, originally from Sagami Province, who were retainers of the powerful Akamatsu clan. In the Edo period, the area became part of the holdings of Akō Domain. The village of was established with the creation of the modern municipalities system on April 1, 1889. It was raised to town status on January 1, 1913, becoming . The town merged with the neighboring town of Naba on April 1, 1939 and the reading of the kanji of its name was officially changed to "Aioi" on April 13, 1939. It was raised to city status on October 1, 1942. Aioi merged with the villages of Wakasano and Yano on April 1, 1954. Government Aioi has a mayor-council form of government with a directly elected mayor and a unicameral city council of 14 members. Aioi contributes one member to the Hyogo Prefectural Assembly. In terms of national politics, the city is part of Hyōgo 12th district of the lower house of the Diet of Japan. Economy Aioi has traditionally been famous for shipbuilding, which, despite many years of decline, still maintains a strong presence through Ishikawajima-Harima Heavy Industries (IHI).