Yoshida-Kōriyama Castle

Yoshida-Kōriyama Castle (吉田郡山城), located in Yoshida Town, Akitakata City, Hiroshima Prefecture, was the main stronghold of the Mōri clan, the Sengoku-era feudal lords of Aki Province. Today, the ruins of Yoshida-Kōriyama Castle have been combined with those of Tajihi-Sarukake Castle and are designated together as the National Historic Site “Mōri Clan Castles: Tajihi-Sarukake Castle Ruins and Kōriyama Castle Ruins.”

The castle was built on Mount Kōriyama, on the northern side of the Yoshida Basin, situated between the Kawai River (Enokawa River) and the Tajihi River. Originally, it was only a small fort, but as the power of the Mōri clan expanded, the castle was steadily enlarged until it covered the entire mountain. Its massive scale made it one of the most formidable fortresses in the Chūgoku region of the time.

Under Mōri Motonari’s leadership, Yoshida-Kōriyama Castle became the strategic base from which the clan unified the Chūgoku region. Many famous battles and military strategies were planned and executed here. Later, when Mōri Terumoto relocated to the newly constructed Hiroshima Castle, Yoshida-Kōriyama gradually faded from the historical stage.