Shiryōkaku (四稜郭) (literally, 'four-point fort') is a fort in the city of Hakodate. It was constructed in April 1869, during the Battle of Hakodate, three kilometres to the northeast of Goryōkaku by two hundred soldiers of the former Tokugawa shogunate and a hundred local villagers, likely under the direction of Ōtori Keisuke.
The fort covers an area of 21,500 m2, stretching approximately a hundred metres east to west and seventy metres north to south; the earthworks rise to a height of 3 m with a width of 5.4 m; they are surrounded by a dry moat 0.9 m deep and 2.7 m wide; the entrance is to the southwest.
Shiryōkaku fell to government forces within a few hours on 11 May 1869.
In 1934 the area was designated an Historic Site. Repairs were carried out from 1970-2 and again in 1990.
References:Kakesbeck is one of the largest medieval fortifications in Münsterland and the oldest castle in Lüdinghausen. The imposingly grown complex originated in 1120 as a motte, a small hilltop tower castle. After numerous changes of ownership, the castle was extended onto two islands, but it was not until the 14th century that it underwent significant alterations and extensions under the von Oer family. The estate experienced its heyday in the middle of the 18th century, when it covered an area of almost one square kilometre and consisted of five further outer castles in addition to the core castle, which were secured by ramparts and moats.
The well-maintained condition of the castle today is thanks to the late Wilfried Grewing, the former lord of the castle. The foundation named after him has been particularly committed to preserving the property since 2020.