Kururi Castle also known as U Castle Kimitsu, Chiba Prefecture.
Built by the Mariyatsu Takeda in 1540, Kururi Castle later came under the command of Satomi Yoshitaka, who used it as his base of operations against the Hōjō clan, based at Odawara Castle.
The Hōjō attempted to take Kururi Castle on four occasions, but were unable to scale it's defences which on one side consists of a sheer cliff face.
The Hōjō finally seized the castle in 1564 after a month long siege involving the use of samurai infiltrators (ninja) who were able to taint the water supply and wreak havok from within the castle grounds.
The Hōjō lost the castle a mere three years later in 1567, when Satomi once again gained control of it by using his unique knowledge of the terrain and castle defences.
Following the Battle of Sekigahara in 1600, Kururi castle was ruled by the Osuga Clan, Tsuchiya, and Kuroda.
In 1872, during the Meiji Restoration, the castle was completely demolished and the materials were used in the village below to build canals and a school.
Kururi Castle's ruins today are a park and in 1979 a reproduction of the keep was constructed out of concrete. It contains the castle's museum and stands on a stone base beside the original castle's foundations which are left intact and protected.
A legend says that when the original Kururi Castle was being constructed, it rained twenty-one times or, on average, once every three days. This is how it received its alternate name- U Castle (Rain Castle).