Tsukurōmi Castle, Japanese castle in Futtsu, Japan

Tsukurōmi Castle is a mountain castle in Takeoka, Futtsu, Chiba Prefecture, built on an independent north-south ridge facing the Uraga Channel, with its west side protected by the channel and its north side by the Shirako River. Four enclosures lie along the ridge, with further enclosures on a western spur and upper valley. Remains include dry moats, stone walls, earthen ramparts and a well, mixed with earthworks from batteries added in the late Edo period.

Built in 1461 by Mariyatsu Nobuoki, or possibly Takeda Nobunaga, the castle passed to Mariyatsu Nobumasa during the 1534 succession dispute. In 1537 Satomi Yoshitaka took it and installed the Masaki family. After the 1590 Odawara campaign the Satomi were reduced to Awa Province and the castle was abandoned.

The castle's name is written 造海城, read Tsukurōmi-jō. It was held by the Mariyatsu and later the Satomi, and after the 1590 Odawara campaign the Satomi were reduced to Awa Province alone and the castle was abandoned. In the late Edo period two gun batteries (daiba) were built at the northern and south-western ends of the grounds, so late-period earthworks now sit among the medieval ones.

Visitors should know that the castle site exists today as ruins spread across open ground that can be explored on foot. Comfortable shoes and weather protection are important since the remains are not covered structures.

The hilltop keep was largely left intact, but two gun batteries (daiba) were added at its northern and south-western ends in the late Edo period, so late-19th-century earthworks stand beside medieval ones. Visitors can also find a spot called Kideine near the base of the main ridge, where a supplementary terrace (koshikuruwa) was built.