Located near to the Asian Continent, the area of present-day Yamaguchi Prefecture fell under the influence of the continental culture earlier than most of the rest of Japan, and people of this area grew rice using techniques introduced here around BCE 3rd to 2nd century.
After that, the Yamato Empire united the nation around 4th to 5th century, and placed six kuni-no-miyatsuko and one agata in the area of present-day Yamaguchi Prefecture, and united the area with Suo Province and Nagato Province.
From the Heian period to the Kamakura period (794 to 1333), local samurai groups enhanced their presence, and the Ouchi and Toko clans established their own positions in Suo Province and Nagato Province, respectively. In the Muromachi period (1338 to 1573), Ouchi Hiroyo, the 24th head of the Ouchi clan defeated Bofu and Nagato, and built a city in Yamaguchi modeled after Kyoto, as well as introducing the continental culture, and accumulating wealth through trade with Korea and Ming China. As a result, Yamaguchi began to be called the western Kyoto, with the blossoming of the splendid culture of the Ouchi clan.
The flourishing Ouchi clan began to lose influence after the 31st head Yoshitaka was defeated by his retainer Sue Harutaka, and Mori Motonari, who defeated Sue, had a hegemony over the almost entire Chugoku region.
However, after being defeated by the eastern troops led by Tokugawa Ieyasu at the battle of Sekigahara in 1600, the Mori clan had their yield reduced to 369,000 koku, and built a residence in Hagi. From this onward, the Mori clan strived to strengthen the financial basis of their domain adopting the economic measure of encouraging the production of the “three white things of Bocho”: salt, rice and paper. Moreover, the domain took the initiative in steps toward the Meiji restoration, producing many excellent human resources, including Yoshida Shoin and Takasugi Shinsaku, and played a leading role in the creation of a modern state.
After the Tokugawa shogunate fell and the Meiji administration started their rule in 1868, present-day Yamaguchi Prefecture was founded in 1871, when the feudal domains were abolished and prefectures were established instead. The Meiji administration adopted many new systems and promoted modernization policies, including the introduction and promotion of modern industry, in particular. Although the prefecture saw some signs of new-born modern industry, including cement production and the establishment of machine-based filature plants, the main industry of the prefecture remained agriculture during the Meiji Era.
From the beginning of the Taisho Era, favorable conditions in Yamaguchi Prefecture, including abundant mineral resources and a blessed harbor environment, triggered a series of construction of dockyards, and chemical, machine, metal and other plants in the Seto Inland Sea coastal area. The prefecture continued its industrial growth in the Showa Era, with a large-scale petrochemical complex built here after WWII, resulting in the prefecture’s further development as a leading industrial prefecture in Japan.