Introduction: Shrinking Japan, the Goki-Shichido, the Sannyodo, the Municipal Power, and the Methodology

This is theGoki-Shichido fourth volume of Shrinking JapanShrinking Japan andRegional variations Regional VariationsMunicipal power from the current author, focused along the SannyodoSannyodo under the Goki-Shichido. The world population reached 8 billion in 2022, although the population increase ratePopulation increase rate has been slowing down. The Japanese population has been declining, with “shrinking Japan” starting in 2008. However, the situation of shrinking JapanShrinking Japan differs from one prefecture to another, and even within the same prefecture it varies from the east to the west, and from the north to the south. In other words, Japanese society today can be described as shrinking Japan with regional variationsRegional variations. Then, what is the situation of the shrinking population in the Sannyodo? The SannyodoSannyodo in ancient times located in the southern part of the Chugoku regionChugoku region. It comprised eight ancient provinces. The borders of AkiAki (western part of HiroshimaHiroshima Prefecture today) and SuoSuo (eastern part of Yamaguchi PrefectureYamaguchi Prefecture today) provinces were established in 734. HarimaHarima (southwestern part of Hyogo PrefectureHyogo Prefecture today), MimasakaMimasaka (northern part of Okayama PrefectureOkayama Prefecture today), and BizenBizen (southeastern part of Okayama Prefecture today) provinces were designated as kingokuKingoku in the Engi-shikiEngi-shiki. BicchuBicchu (western part of Okayama PrefectureOkayama Prefecture today) and BingoBingo (eastern part of Hiroshima PrefectureHiroshima Prefecture today) provinces were designated as kingokuKingoku, while SuoSuo, and NagatoNagato (northwestern part of Yamaguchi Prefecture today) provinces were ongokuOngoku. Of the ShichidoShichido, the most important circuit in ancient times was the SannyodoSannyodo, not the TokaidoTokaido. The Sannyodo connected KyotoKyoto and DazaifuDazaifu. The importance of SannyodoSannyodo in ancient times rests upon the existence of Dazaifu. Dazaifu was the Government Headquarters established in ChikushiChikushi County, ChikuzenChikuzen Province in KyushuKyushu from the latter part of the Yamato periodYamato period through the Heian periodHeian period to manage foreign affairs and control KyushuKyushu. In ancient times, the entire SaikaidoSaikaido (KyushuKyushu) area was put under the administration of DazaifuDazaifu, and the government office was given the authority to defend against foreign invaders and to act as a diplomatic contact. From perhaps as early as the 3rd century, special officials were stationed in northern Kyushu to regulate contacts with ChinaChina and ChosenChosen (Korea today). As a result, the Sannyodo connecting the KinaiKinai and Dazaifu was the most important transportation route for the Imperial CourtImperial Court. For this reason, the SannyodoSannyodo was the only DairoDairo of the ShichidoShichido, and the TokaidoTokaido was classified into the ChuroChuro rather than the Dairo. For the in-depth study of along the SannyodoSannyodo, both the HiroshimaHiroshima and Yamaguchi prefectures have been selected.