As a result, he became a shugo daimyo with the territories of six provinces, such as Izumi Province, Kii Province, Suo Province, Nagato Province, Buzen Province and Iwami Province, and built the height of the Ouchi clan's prosperity, along with the trading with Yi Dynasty Korea on its own accord.
結果、和泉国・紀伊国・周防国・長門国・豊前国・石見国の6カ国を領する守護大名となり、李氏朝鮮とも独自の貿易を行うなどして大内氏の最盛期を築き上げた。