Prefecture Hill - Agatazaka

...With the inns of Narai to the north and Yabuhara to the south, this was the most difficult part of the Nakasendo. This pass was created when the Kisoji road was opened in 702 (Taiho 2), and was called Agatazaka at the time. The name of the pass is said to come from the fact that Kiso Yoshimoto erected a torii gate to give thanks to the gods after winning a battle during the Sengoku period.

*Some of the terminology that refers to "Kenzaka" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…北側に奈良井，南に藪原の宿があり，中山道随一の難所であった。702年(大宝2)岐蘇路（きそじ）の開削とともにこの峠が生まれたが，当時は県坂（あがたざか）と呼ばれた。地名の由来は戦国時代，木曾義元が戦いに勝った時に，鳥居をたてて神に感謝したことにあるという。…

※「県坂」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報