Akechi Castle, Mountain fortress in Ena, Japan

Akechi Castle, also called Shirataka Castle, is a Sengoku-period yamajiro in Akechi, Ena, Gifu Prefecture, built on a 530 m hill. It is a hirayama-style fort with 23 earthen baileys of varying size, their original forms still visible; key positions were faced with stone walls and held five residential buildings used as jinya.

The fortress was founded in the 13th century and remained an important outpost during conflicts between local warlords over many generations. It was later abandoned and today stands as a ruin reflecting the history of Japan's feudal period.

The castle is also called Shirataka Castle, and the surrounding area gave the Akechi-Tōyama clan its name. The five halls that once stood inside the earthworks were wartime quarters, not residences surviving today; only the earthen ramparts and some stone-faced redoubts remain. The site is a prefectural-designated historic site.

The route to the hilltop passes through forest paths where comfortable walking shoes are recommended, especially during wetter months. The return journey takes roughly the same amount of time as the climb, so bring adequate water and sturdy footwear.

The original earthen walls remain intact today, making this site rare among Japanese castles. These unaltered defensive structures give visitors a direct sense of how medieval mountain fortresses actually appeared.