 On January 1, 2006, the towns of Takajō, Takazaki, Yamada and Yamanokuchi (all from Kitamorokata District) were merged into Miyakonojō.Miyakonojō is known as the birthplace of the Shimazu Estate, the largest shōen (estate or manor) of medieval Japan.In the 1020s, a powerful official named Taira no Suemoto developed a small manor named Shimazu-in.