Mōri clan

The Mōri clan (毛利氏 Mōri-shi) was a family of daimyōs, descended from Ōe no Hiromoto and established themselves in Aki Province. Their name was derived from a shōen in Mōri, Aikō District, Sagami Province. Hiromoto's descendants began to name themselves the Mōri.

After the Jōkyū War, Mōri was appointed to the jitō office of a shoen in Aki Province. During the Kamakura period Mōri was one of prominent Gokenin family due to the fame of their ancestor Hiromoto. At the end of the Kamakura Shogunate, Mōri was distant from the shogunate and showed a favorable attitude to Ashikaga Takauji.

In the Sengoku period, Mōri Motonari expanded their power to the whole of Aki province and then to other neighboring provinces. In his generation, Mōri became the daimyō from a local Gokenin.

During the war with the Oda clan and the Ikkō-ikki, the Mōri helped the Ikkō-ikki clan by establishing a naval trade route between each other's provincial docks and harbours, the Oda eventually nullified this by laying siege to the trade ships between the two clans and went to further disrupt trade by attempting to destroy the Mōri fleet, failing on their first attempt in 1571. The second battle took place in 1579 with the Oda sending eight Atakebune (heavily armoured ships with iron-clad plating) warships to finally destroy the Mōri naval threat.

After a struggle between Toyotomi Hideyoshi, who led his army as a general of Oda Nobunaga, the two sides made peace and Mōri remained as a daimyo who kept five provinces in Chūgoku. In 1600, Mōri Terumoto nominally led the West Army in the Battle of Sekigahara. The West Army lost the battle and the Mōri clan lost three eastern provinces and moved their capital from Hiroshima to present-day Hagi, Yamaguchi. The newer fief, Mōri han, consisted of two provinces: Nagato Province and Suō Province. Derived from the former, Mōri han was referred to often as Chōshū han.

After the Meiji Restoration, the han and daimyō system was abolished, and the head of the Mōri was titled as duke.