Inohana Castle (亥鼻城 ), also known as Chiba Castle, is located in Chiba City and was constructed on the Inohana Plateau, close to the present-day Chiba Prefectural Office. The Chiba clan (千葉氏), a cadet branch of the Kanmu Heike clan,* established a fortification there as early as 1126. For some 330 years, the town prospered as an important commercial and cultural center in Kanto area, along with Kamakura.
In 1455, Makuwari Yasutane (馬加胤持) a retainer related to the clan, defeated the Chiba and took their name. Yasutane's son Suketane abandoned Inohana Castle and moved to Motosakura Castle (本佐倉城). Thereafter, Chiba Castle did not play any significant role in history anymore.
The castle grounds are now surrounded by Inohana Park.
At the northern edge of the park, there is a turret-shaped building resembling a Japanese donjon which houses the Chiba City Folk Museum. The donjon was completed in 1967, but does not reflect the design of the original fortification. The museum displays artifacts relating to the history of the region and the Chiba clan.
The statue of the Chiba Tsunetane (千葉常胤, 1118–1201) in front of the castle aims right at the building!
I recommend to visit the museum, because it has plenty of interesting exhibits on the Chiba clan and a moderately good view from the panoramic visitor platform on the top floor.
Date of visit : 12 May 2013
* The Taira clan (平氏), also known as the “Heike”, an alternative reading of the characters for “Taira family”, descended from a prince who had been reduced to commoner status in the practice of dynastic shedding common throughout Japan’s classical age. The prince was a son of the Emperor Kanmu (r. 781-806) and was given the surname "Taira". His descendants are referred to as the Kanmu Heike.