Hiroshima Prefecture Along the Sannyodo of the Goki-Shichido and Regional Variations

HiroshimaHiroshima Prefecture, located in the ancient SannyodoSannyodo of the Goki-ShichidoGoki-Shichido, consists of the previously named AkiAki and BingoBingo provinces. SannyodoSannyodo was the only dairoDairo among the seven circuitsSeven Circuits developed as the largest arterial road connecting the capital of KyotoKyoto and Dazaifu, which was a crucial gateway to eastern Japan and ChinaChina. According to the 2020 national census, the population of Hiroshima PrefectureHiroshima Prefecture was 2,799,702, a decrease of 44,288 (−1.6%) from the previous national census in 2015. The prefecture accounts for 2.2% of Japan’s total population (126,146,099), making it the 12th largest in the country. It is noteworthy that the current foreign resident populationResident population in Hiroshima prefecture represents 1.9% (52,891) of the entire prefecture’s populace. The prefecture is divided into three areas (Aki-Hiroshima, BingoBingo, and BihokuBihoku), comprising 23 municipalities today. Looking at the projected population increase rate from 2015 to 2045 by prefecture level, Hiroshima PrefectureHiroshima Prefecture ranks 9th among the total 47 prefectures (−14.6% against the national average of −16.3%). However, a more detailed analysis by municipality reveals significant variations within the prefecture (from the highest of Higashihiroshima-shiHigashihiroshima-shi: −5.5%, followed by Saka-choSaka-cho: −5.6% to the lowest of Akiota-choAkiota-cho: −56.1%). Intriguingly, these three municipalities are all in the same Aki-Hiroshima areaAki-Hiroshima area today. The progress of shrinking JapanShrinking Japan, however, seems to be accelerating in the Bingo-BihokuBihoku area much faster than other areas in the prefecture (−36.7% against the prefectural average of −14.6%). In fact, the marriage power (X) on the population sustaining power (Y) for 23 municipalities in HiroshimaHiroshima Prefecture in 2013 is significant at 0.001 level (Y = −3.627 + 0.638X, variance explained R2 = 0.751, p = 0.000). The marriage powerMarriage power in 2015 of Higashihiroshima-shiHigashihiroshima-shi (4.62‰) and of Akiota-cho (2.47‰) are indicative of their projected population increase ratePopulation increase rate for 2045. Thus, we can say that the theoretical hypothesis of the Goki-ShichidoGoki-Shichido and regional variationsRegional variations is also validated for Hiroshima PrefectureHiroshima Prefecture. Hiroshima-shiHiroshima-shi, designated as an ordinance city, is composed of eight wards, each displaying significant variation in the projected population for 2045 (Hiroshima-shi: −6.0%; the highest of Naka-kuNaka-ku: 6.4%; the lowest of Asakita-kuAsakita-ku: −29.4%) highlighting the significance of the regional variation perspective. Akiota-choAkiota-cho, a ward where nearly 90% of the land is covered with forests, has such an acute decline in the population that we might assume that there is no positive municipal powerMunicipal power in the community. On the contrary, during the coronavirus pandemicCoronavirus pandemic, Akiota-cho attracted more tourists—most likely due to people’s preference for being outdoors, enjoying nature, and experiencing the forest therapyForest therapy. Thus, with the increase of the kankei-jinko (related populationRelated population), Akiota-choAkiota-cho is here to stay, and we discuss the town’s unresolved challenges.