The was a shà Âen (estate or manor) in southern Kyushu of Japan, covering large portions of Satsuma, à Âsumi and Hyà «ga Provinces. It was the largest shà Âen of medieval Japan. The Shimazu clan took its name from this estate as the clan succeeded the position of jità  (land steward).
No contemporary source recorded the foundation of the Shimazu Estate. According to a document dated circa 1291, a "wasteland belonging to no one" was developed during the Manju era (1024âÂÂ1028) and was donated to Kampaku (de facto ruler of Japan) Fujiwara no Yorimichi to break free from the provincial government's control. Another document states that its founder was Taira no Suemoto, the Dazai Daigen (high-ranking official of the administrative center of Kyà «shà «). It is likely that Taira no Suemoto was the founder of the Chinzei Heishi, a branch line of the Taira clan in Kyushu. A notable member of the Chinzei Heishi was Ata Tadakage.
The Shimazu Estate originally covered Shimazu, Morokata District of southern Hyà «ga Province (modern-day Miyakonojà Â, Miyazaki Prefecture) but was soon expanded into the neighboring lands of the province. Under the patronage of the powerful Fujiwara clan, Taira no Suemoto exercised effective administrative control over the lands. In 1029, Taira no Suemoto even raided the government office of the neighboring à Âsumi Province but a fragmentary sources suggest that he was not punished severely.
The Shimazu Estate was expanded substantially in the first half of the 12th century. Large portions of Satsuma, à Âsumi (including the island of Tanegashima) and southern Hyà «ga became part of the estate, either as ichien no shà  (estate under complete control) or yose gà Âri (where tax revenue was shared with the provincial government).
The Shimazu Estate was inherited by the Fujiwara family, but came under the control of the Taira clan in the second half of the 12th century. Yorimichi's 6th generation descendant, Kampaku Fujiwara no Motozane, was married to Taira no Moriko, a daughter of Taira no Kiyomori. After Motozane died in 1166, his widow Moriko managed the property of the Fujiwara clan. After Moriko's death in 1179, the estate was inherited by the Konoe branch family of the Fujiwara clan.
With the establishment of the Kamakura shogunate, supporters of the Taira clan were replaced by the shà Âgun's retainers. In 1185, Koremune no Tadahisa was appointed as jità  of the Shimazu Estate. Although he was originally a retainer of the Konoe family, he moved in an inner circle of the shogunate for his kinship ties with the first shà Âgun Minamoto no Yoritomo and his powerful retainer Hiki Yoshikazu. He was also appointed as the military governor of Satsuma, à Âsumi and Hyà «ga Provinces. Thereafter he claimed the clan name of Shimazu, which indicated the ownership of the estate.
By the time Tadahisa took the position of jità Â, the Shimazu Estate occupied 70% of agricultural fields of Satsuma Province although over 70% of the lands were yose gà Âri and were not under the estate's full control. A small portion of the Shimazu Estate in Satsuma was controlled by the Chiba clan. In Satsuma, the provincial government was fused with the Shimazu Estate, as a large overlap in membership between the two polities is observed. The Shimazu Estate's area of influence was smaller in à Âsumi Province, being just over half, and the largest part of the remaining portion was controlled by à Âsumi Shà Â-Hachimangà «. However, it had a stronger control over the land, as over half of the lands were ichien no shà Â. The provincial government and the estate remained largely separate entities.
In 1203, Shimazu Tadahisa was ousted from his positions as a jità  of the estate and the military governor of the three provinces because his relative Hiki Yoshikazu was annihilated by the Hà Âjà  clan. He managed to regain the posts of the jità  of the Shimazu Estate in Satsuma (1213) and the military governor of Satsuma Province (1205). However, the jità  of the estate in à Âsumi and the military governor of à Âsumi Province were succeeded by the Hà Âjà  clan. The Nagoe branch family of the Hà Âjà  clan maintained the post of jità  in à Âsumi until the end of the Kamakura period. They sent the Higo clan to à Âsumi as deputy rulers. After the Hà Âjà  clan was annihilated, one line of the Higo clan made itself autonomous in Tanegashima and began to claim the clan name of Tanegashima. The post of the military governor of à Âsumi Province was transferred from the Nagoe family to the Chiba clan in the early 1280s and then to the Kanesawa branch family of the Hà Âjà  clan in the early 1290s. Because the Nagoe family kept the position of the jità  of the estate in à Âsumi, the military governor had to devote much effort to consolidate power. In fact, Kanesawa Tokinao actively incorporated the officials of the military government as his retainers and relabeled their lands as the "private territories of the military governor" (å®ÂèÂ፤Âé Â).
Even in Satsuma Province, the Shimazu clan's rule was not stable. As a result of the Jà Âkyà « War, Satsuma's Kawanabe District came under the control of the Tokusà  (mainline) family of the Hà Âjà  clan. Hà Âjà Â's retainer, the Chikama clan, served as the district governor and deputy jità  of Kawanabe District.
During the downfall of the Kamakura shogunate, Shimazu Sadahisa successfully sided with Ashikaga Takauji. In reward for his service, the Shimazu clan won back the jità  of the Shimazu Estate in à Âsumi and the military governor of à Âsumi and Hyà «ga Provinces. Because the military government and the estate in à Âsumi remained distinct entities, the Shimazu clan had much trouble regaining control over the province and eventually collapsed.