Saiki Castle is classified as a hilltop castle (its layout: Renkakushiki), and is located in Ōita Prefecture. During the pre-modern age, it found itself within the borders of Bungo Province. It is associated with the Mōri clan. Dates in use: 1606 - 1871.

When Mōri Takamasa came here from his lands in Hita to the west, he had Togamure castle built. It was soon realised that its location was unsuitable for the administration of the domain & a new castle was built atop Mt. Hachiman. The castle's name at that time was Tsuruya Castle but in modern times it is more commonly known as Saiki Castle. Originally there were five multi-storied turrets, one single-storied turret & seven gates.

The stonework of the Hon-maru, Kita-no-maru & Nishi-no-maru remain in very good condition. The bases of all turrets & gates are still clearly visible. At the base of the mountain is The San-no-maru gate. The gate is rather large & was originally built in the Edo period.

Timeline

1601	Mōri Takamasa was transferred here.
1606	The castle was completed.
1617	A fire originating in the Ni-no-maru destroyed the Hon-maru (main enclosure) & the main tower.
1637	The castle was expanded when another enclosure, the San-no-maru, was built at the base of the mountain to house the domain's administrative headquarters. The surviving gate dates from this period.
1726	The San-no-maru Gate was renovated.
1832	The San-no-maru Gate was once again renovated.
1869	Control of the castle & its surrounds were handed back to the Emperor.

Historical recognition

San-no-maru Gate

Prefectural Historic Site