Chiba-shi

Descendants of Tadatsune, of the Yoshibumi line of Kanmu Heishi. The family name is the place name of Chiba in Shimousa Province. It is not clear when the clan began to call itself the Chiba clan, but it is thought that the Chiba Manor of the Hachijo-in Estate was established during the Gen'ei era (1118-1120), and Tadatsune's fourth-generation descendant Tsuneshige was called "Chiba Daifu" at the Kebiisho office of the manor, so it must have been in the early 12th century. His son Tsunetane became the guardian of Shimousa in response to Minamoto no Yoritomo's uprising in 1180 (Jisho 4), and thereafter the direct line of the clan was called Chiba no Suke, also serving as Shimousa Gon no Suke. The family flourished during the Kamakura period, partly due to the death of their relative, Kazusa no Suke Hirotsune, by Yoritomo, and gained many territories in Shimousa, Kazusa, Mutsu, Mino, Iga, Kyushu, and other areas, prospering in each region. Although there were conflicts between the family during the turbulent times of the Northern and Southern Courts and Muromachi periods, they held the position of Shimousa Shugo and were the most powerful pillars of the Koga Kubo. However, the main family split into two branches in the mid-15th century, and Tonojoen of Mino temporarily moved to Tonosho (Tonosho Town, Katori City, Asahi City, Katori County, Chiba Prefecture, and other areas) and unified the area, but gradually declined under the pressure of emerging forces such as the Hojo and Satomi. The Soma, To, Kokubu, and Osuga clans are all members of this clan, and many members of the clan use star crests due to their faith in Myoken.

[Toyohiko Fukuda]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

良文流(よしぶみりゅう)桓武平氏(かんむへいし)、忠常(ただつね)の子孫。下総国(しもうさのくに)千葉の地名を姓とする。いつから千葉氏と称するかは明確でないが、八条院領千葉庄(ちばのしょう)の成立は元永(げんえい)年間（1118～1120）と考えられ、忠常4代目の子孫常重(つねしげ)は当荘検非違所(けびいしょ)で「千葉大夫」と称しているので12世紀初期であろう。その子常胤(つねたね)は1180年（治承4）の源頼朝(みなもとのよりとも)の挙兵に応じて下総の守護となり、以後その嫡流は下総権介(しもうさごんのすけ)を兼ねて千葉介と称した。同族の上総介(かずさのすけ)広常が頼朝に討たれたこともあって、鎌倉時代に大いに発展し、下総、上総をはじめ陸奥(むつ)、美濃(みの)、伊賀、九州などに多くの所領を得、それぞれの地域で繁栄する。南北朝・室町時代の争乱期には一族間の抗争もあるが、下総守護職を保持し、古河公方(こがくぼう)のもっとも有力な支柱であった。しかし、本宗家は15世紀なかばに2流に分裂、美濃の東常縁(とうのじょうえん)が東庄(とうのしょう)（千葉県香取(かとり)郡東庄町、香取市、旭(あさひ)市ほか）に一時下向(げこう)して統一を果たすが、北条、里見(さとみ)らの新興勢力に押されてしだいに衰える。相馬(そうま)、東(とう)、国分(こくぶ)、大須賀(おおすが)などの各氏はこの一族で、一族には、妙見(みょうけん)信仰によって星辰(せいしん)の家紋を用いる者が多い。

［福田豊彦］

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