{ "id": "epvgade7nm", "slug": "oomi", "title": "Ōomi", "updated": "2026-10-15", "topic_path": [ { "id": "society", "label": "Society and history", "api_url": "https://www.edgepedia.org/api/v1/topics/society" }, { "id": "society.history", "label": "History and archaeology", "api_url": "https://www.edgepedia.org/api/v1/topics/society.history" }, { "id": "society.history.asia", "label": "Asian history", "api_url": "https://www.edgepedia.org/api/v1/topics/society.history.asia" }, { "id": "society.history.asia.japan", "label": "Japan", "api_url": "https://www.edgepedia.org/api/v1/topics/society.history.asia.japan" }, { "id": "society.history.asia.japan.jp-yamato", "label": "Yamato and Kofun Japan, from Himiko to the great tombs (3rd century to 592)", "api_url": "https://www.edgepedia.org/api/v1/topics/society.history.asia.japan.jp-yamato" } ], "geo": [ { "id": "geo.asia.t500.society.history.asia.japan", "label": "Asia (other) · 500 BC to AD 999: Japan", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500.society.history.asia.japan", "path": [ { "id": "geo.asia", "label": "Asia (other)", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia" }, { "id": "geo.asia.t500", "label": "Asia (other) · 500 BC to AD 999", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500" }, { "id": "geo.asia.t500.society", "label": "Society and history", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500.society" }, { "id": "geo.asia.t500.society.history", "label": "History and archaeology", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500.society.history" }, { "id": "geo.asia.t500.society.history.asia", "label": "Asian history", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500.society.history.asia" }, { "id": "geo.asia.t500.society.history.asia.japan", "label": "Japan", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.asia.t500.society.history.asia.japan" } ] } ], "excerpt": "The Ōomi (大臣) was the chief ministerial title of the Yamato court, held by Ōmi-kabane clan heads and abolished at the Taika Reform of 645.", "snippet": "The Ōomi (大臣) was the chief ministerial title of the Yamato court, held by Ōmi-kabane clan heads and abolished at the Taika Reform of 645.", "node": "society.history.asia.japan.jp-yamato", "markdown": "# Ōomi\n\nThe Ōomi (大臣) was the chief ministerial title of the Yamato court, held by the head of a powerful lineage bearing the Ōmi (臣) kabane and ranking alongside the Ōmuraji (大連) as the highest executive office of the archaic Japanese state.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) The title was abolished at the [Taika Reform](https://www.edgepedia.org/taika-reform) of 645, after which the ritsuryō (Japan's ancient statutory law governmental system) posts of Sadaijin and Udaijin (Minister of the Left and Minister of the Right) took over its standing.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) • [2](https://yoropara.org/nihonshiyogo/ooomi/)\n\n| | |\n|---|---|\n| **Native name** | 大臣 (Ōomi) |\n| **Holder** | Head of an uji holding the Ōmi (臣) kabane[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) |\n| **Counterpart office** | Ōmuraji (大連), held by Ōmi (連)-kabane clans[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) |\n| **Abolished** | Taika 1 (645), at the Taika Reform[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) • [2](https://yoropara.org/nihonshiyogo/ooomi/) |\n\n## Founding and history\n\nThe [kabane system](https://www.edgepedia.org/kabane-system) ranked the hereditary titles conferred on the chieftains (uji no kami) who served the Yamato court; the Ōmi and Muraji titles went to chieftains in service at the court itself, while kimi, atae, and obito went to regional chieftains.[3](https://jref.com/articles/yamato-court.197/) From among the clans holding the Ōmi kabane the court chose the Ōomi, who presided over those lineages.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html)\n\nOrigins. Because the title arose before any written regulations existed, there was no fixed number of holders.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) One reference work dates the beginning of the title to the latter half of the 5th century.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) \n\nFour of the seven clans that claimed the legendary [Takeuchi no Sukune](https://www.edgepedia.org/takeuchi-no-sukune) as ancestor held the Ōomi title: the Soga, Kose, Heguri, and Katsuragi.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html)\n\n## Structure and functions\n\nThe Ōomi stood at the head of the Ōmi-kabane uji and took part in government alongside the Ōmuraji, who presided over the Muraji-kabane clans such as the Ōtomo and Mononobe.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) \n\nA [University of Tokyo](https://www.edgepedia.org/university-of-tokyo) dissertation on the pre-Taika polity proposes a different reconstruction: through source criticism of the [Nihon Shoki](https://www.edgepedia.org/nihon-shoki) it estimates that the office of Ōmuraji never actually existed, and that in the first half of the 6th century, under [Emperor Kinmei](https://www.edgepedia.org/emperor-kinmei), the posts of Mahetsukimi and, above them, Ōmahetsukimi (大臣) were created as offices of deliberation, attendance, and reporting, in a period of division within the royal house and breakdown of diplomacy toward Korea. In this reading the Ōmahetsukimi–Mahetsukimi body was a clan council of one representative each of the powerful Kinai clans.[4](https://gakui.dl.itc.u-tokyo.ac.jp/cgi-bin/gazo.cgi?no=213578)\n\n## Political influence\n\nThe Ōomi and Ōmuraji together formed the top executive layer of the Yamato polity under the Ōkimi (great king).[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) • [2](https://yoropara.org/nihonshiyogo/ooomi/) In the late 6th century the Ōomi Soga no Umako destroyed the Ōmuraji Mononobe no Moriya, and the long-standing arrangement in which Ōomi and Ōmuraji stood side by side under the great king collapsed.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) After Empress Suiko's reign, Soga-line officials came to occupy one third of the membership of the deliberative council, changing its character.[4](https://gakui.dl.itc.u-tokyo.ac.jp/cgi-bin/gazo.cgi?no=213578)\n\n## End\n\nThe Ōomi title was abolished at the Taika Reform.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) In the [Isshi Incident](https://www.edgepedia.org/isshi-incident) of 645, the coup by Prince Naka no Ōe and Nakatomi no Kamatari, the Ōomi Soga no Iruka was killed and [Soga no Emishi](https://www.edgepedia.org/soga-no-emishi) killed himself by setting fire to his house, ending the main Soga line.[2](https://yoropara.org/nihonshiyogo/ooomi/) The court position was thereafter represented by the Sadaijin and Udaijin.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) Under the ritsuryō system these ministers each had a complement of one, ranked shonii or junii, and the Sadaijin in effect presided over the business of the Dajōkan.[5](http://www.sol.dti.ne.jp/hiromi/kansei/o_kan_dajo_daijin.html) \n\n## Assessment and legacy\n\nThe dissertation cited above treats the Soga as the only Ōomi clan of the pre-Taika period and traces the decline of the Soga (Ishikawa/Sogadake) line as a concrete case of the end of the ancient aristocracy.[4](https://gakui.dl.itc.u-tokyo.ac.jp/cgi-bin/gazo.cgi?no=213578) The same work argues that the pre-Taika government was a clan council (the Ōmahetsukimi–Mahetsukimi system) formed by the powerful Kinai uji, rather than a dual Ōomi–Ōmuraji executive.[4](https://gakui.dl.itc.u-tokyo.ac.jp/cgi-bin/gazo.cgi?no=213578) [Reference](https://www.edgepedia.org/reference) works, by contrast, continue to describe the Ōomi and Ōmuraji as paired chief-executive titles of the Yamato court.[1](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html) \n\n## References\n\n1. [古代（氏姓制度・部民制）｜官制大観](http://www.sol.dti.ne.jp/hiromi/kansei/e_kodai.html)\n2. [大臣 | 日本史！よろパラ](https://yoropara.org/nihonshiyogo/ooomi/)\n3. [Yamato Court](https://jref.com/articles/yamato-court.197/)\n4. [学位論文要旨詳細 (University of Tokyo dissertation abstract)](https://gakui.dl.itc.u-tokyo.ac.jp/cgi-bin/gazo.cgi?no=213578)\n5. [太政大臣・左右大臣・内大臣・准大臣｜官制大観](http://www.sol.dti.ne.jp/hiromi/kansei/o_kan_dajo_daijin.html)\n\n---\n*Topic: Encyclopedia › Society and history › History and archaeology › Asian history › Japan › Yamato and Kofun Japan, from Himiko to the great tombs (3rd century to 592)*\n\n*Initially written Sep 24, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/oomi", "markdown_url": "https://www.edgepedia.org/oomi.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Ōomi\", Edgepedia (EdgeChat), https://www.edgepedia.org/oomi. Edgepedia Community License 1.0.", "credit_md": "\"[Ōomi](https://www.edgepedia.org/oomi)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/oomi](https://www.edgepedia.org/oomi). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Ōomi\", Edgepedia (EdgeChat), https://www.edgepedia.org/oomi. Edgepedia Community License 1.0.", "speakable": "The Ōomi was the chief ministerial title of the Yamato court, held by Ōmi-kabane clan heads and abolished at the Taika Reform of 645." }