Born in Suo as a son of Ouchi Masahiro. The Ouchi, based in Yamaguchi, ruled Suo, Nagato, Iwami and Buzen and thrived on Ming trade as the west's top daimyo.
On his father's death he succeeded, quelled uprisings and house strife, and restored Ouchi rule. As the Meio Coup changed shoguns, he strengthened independent power in the west.
He escorted former shogun Yoshiki (Yoshitane) to Kyoto with a large army and restored him as shogun. Allied with Hosokawa Takakuni, he shared bakufu politics. A western daimyo thus moved the center.
He fought Hosokawa Sumimoto's Yoshizumi faction at Funaokayama and won for Yoshitane and Takakuni. Victory near Kyoto secured the bakufu side and raised Yoshioki's fame.
After about ten years in Kyoto he returned to his provinces. Long absence had loosened local control, so he chose to go home—backing the shogun yet putting his base first.
Yoshitane granted him rights to send tally ships to Ming, giving the Ouchi a firm hold on trade profits. Ming and Korean culture gathered in Yamaguchi, a western cultural hub.
Takakuni and Yoshitane fell out and Yoshitane was driven from the capital. Yoshioki in distant Suo could not send enough aid; the gains of his Kyoto march collapsed.
At Ningbo in Ming China, Ouchi and Hosokawa tally-ship men clashed in the Ningbo Incident. The Ouchi won, and for a time they nearly monopolized the tally trade.
Iwami silver mining began to develop, strengthening finances. Using retainers such as the Sue, he kept firm rule centered on Suo and Nagato. Yamaguchi's cultural prosperity continued.
Yoshioki died of illness in his provinces at fifty-two. His son Yoshitaka succeeded. As a western daimyo who restored a shogun in Kyoto, he left a deep mark on early Sengoku politics.
Amago TsunehisaŌuchi YoshitakaAshikaga YoshihideHosokawa Masamoto
Asakura Takakage (Toshikage)Hosokawa KatsumotoŌta DōkanAshikaga YoshimasaAshikaga YoshimiHino TomikoHatakeyama MasanagaHosokawa Masamoto
People of the Muromachi period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.