Yamaguni hamlet, which local legend has it supplied the timber to construct Heian Kyo (ancient Kyoto), had from ancient times possessed deep ties to the imperial house, and the whole area of Yamaguni was in fact a shoen (private estate) under the direct control of the imperial house up until the time of Hideyoshi TOYOTOMI's nationwide land survey.
平安京造都の木材を供給した伝承をもつ山国郷は古くより皇室との関係が深く、山国一円は太閤検地まで禁裏直轄の荘園であった。