The , also known as the , was a domain (han) of the Tokugawa Shogunate of Japan during the Edo period from 1600 to 1871. The Chōshū Domain was based at Hagi Castle in Nagato Province, in the modern city of Hagi, located in the Chūgoku region of the island of Honshu. The Chōshū Domain was ruled for its existence by the tozama daimyō of the Mōri, whose branches also ruled the neighboring Chōfu and Kiyosue domains, and was assessed under the Kokudaka system with peak value of 369,000 koku. The Chōshū Domain was the most prominent anti-Tokugawa domain and formed the Satchō Alliance with the rival Satsuma Domain during the Meiji Restoration, becoming instrumental in the establishment of the Empire of Japan and the Meiji oligarchy. The Chōshū Domain was dissolved in the abolition of the han system in 1871 by the Meiji government and its territory was absorbed into Yamaguchi Prefecture. History The rulers of Chōshū were the descendants of the great Sengoku warlord Mōri Motonari. Motonari was able to extend his power over all of the Chūgoku region of Japan and occupied a territory worth 1,200,000 koku. After he died, his grandson and heir Mōri Terumoto became daimyō and implemented a strategy of alliance with Toyotomi Hideyoshi. This would later prove to be a great mistake. After Hideyoshi's death, the daimyō Tokugawa Ieyasu challenged the Toyotomi power and battled with Hideyoshi's trusted advisor Ishida Mitsunari at the Battle of Sekigahara. Mōri Terumoto was the most powerful ally of the Toyotomi and was elected by a council of Toyotomi loyalists to be the titulary head of the Toyotomi force. However the Toyotomi forces lost the battle due to several factors tied to Mōri Terumoto: His cousin Kikkawa Hiroie secretly made a deal with Tokugawa Ieyasu resulting in the inactivity of 15,000 Mōri soldiers during the battle. His adopted cousin Kobayakawa Hideaki and his 15,600 soldiers betrayed Ishida and joined the Tokugawa side. After assurances from Tokugawa Ieyasu, Terumoto gave up the formidable Osaka castle without a fight. Despite its inactivity, the Mōri clan was removed from its ancestral home in Aki to Nagato Province (also known as Chōshū), and its holdings were drastically reduced from 1,200,000 to 369,000 koku. This was seen as a great act of betrayal to the Mōri clan, and Chōshū later became a hotbed of anti-Tokugawa activities. The origins of this were evident in