The ruins of Oka Castle (Oka-jō), above the town of Taketa in inland Oita, are among the most spectacular and atmospheric castle ruins in Japan. Built on a natural rock plateau high on a steep ridge, this formidable mountaintop fortress once controlled the region, but its buildings were demolished in the Meiji era, leaving only the vast, sweeping stone walls and ramparts perched dramatically along the clifftops. Walking the ruins today, with panoramic views over the surrounding mountains and the Kuju range — especially stunning wreathed in autumn colours or a sea of clouds — is a moving experience. The evocative, melancholy scene is said to have inspired the composer Rentarō Taki, a Taketa native, to write the famous song ‘Kōjō no Tsuki’ (‘The Moon over the Ruined Castle’). Historic, scenic and poetic, Oka Castle is a highlight of inland Oita.
🗓️ At a Glance
| Location | Taketa, Oita |
| Hours | ~9:00–17:00 |
| Admission | Paid (low) |
| Time needed | 1–1.5 hours |
| Best time | Autumn colours; cloud sea |
What to See
- Vast stone walls perched along a high ridge.
- Panoramic views over mountains and the Kuju range.
- Autumn colours or a sea of clouds around the ruins.
- The site that inspired the song ‘Kōjō no Tsuki’.
Combine Your Visit
- Combine with kabosu citrus of inland Oita.
- Pair with the Bungo beef of the region.
- Read our Oita overview .
Getting There
- By car: the practical way to Taketa and the ruins.
- By train + taxi: JR to Bungo-Taketa, then up to the ruins.
Tips
Wear sturdy shoes for the walk up and around the extensive clifftop stone walls, and come in autumn for the maple colours or on an early morning for a chance of the atmospheric sea of clouds. Take in the panoramic mountain views, imagine the song ‘Kōjō no Tsuki’ it inspired, and explore the historic town of Taketa below.
