Tainei-ji incident participant Sue Harukata
The Tainei-ji incident (大寧寺の変, Taineiji no Hen) was a coup in September 1551 by Sue Takafusa (later known as Sue Harukata) against Ōuchi Yoshitaka, hegemon daimyō of western Japan, which ended in the latter's forced suicide in Tainei-ji, a temple in Nagato Province. The coup put an abrupt end to the prosperity of the Ōuchi clan, though they ruled western Japan in name for another six years under the figurehead Ōuchi Yoshinaga, who was not related to the Ōuchi by blood.Aftermath
After the coup, Takafusa invited the younger brother of Ōtomo Sōrin, Haruhide, as the new head of the Ōuchi clan since this was promised to the Ōtomo in order to gain their support. Ōtomo Haruhide hence became known as Ōuchi Yoshinaga, but Sue Takafusa (known as Sue Harukata after the coup) remained the one pulling the strings behind the scenes. This arrangement alienated his co-conspirators, since they agreed only that Yoshitaka be overthrown in favour of his son. Now that both were dead, Sue Harukata placed the blame on Sugi Shigenori and put him to death. Apprehensive of further purges by Harukata, Naitō Okimori went into retirement and died in 1554.
Mōri Motonari bided his time until 1554, when he declared that the emperor ordered him to punish those who killed Yoshitaka, and rebelled against the nominal Ōuchi government. Sue Harukata was driven to suicide by his defeat at the hands of Motonari in the Battle of Itsukushima in 1555, and in 1557 Ōuchi Yoshinaga followed. The Mōri came to possess the Ōuchi lands in western Honshu hereafter.The city of Yamaguchi was burned during the coup, and looting and violence ran rampant for days after the coup had ended. The Jesuit Juan Fernández, who was at the scene of the chaos in Yamaguchi with Cosme de Torres, described the ensuing violence as "so destructive and deadly that the town was on fire and overflowed with blood for the space of eight days; for with the laws in abeyance, victorious wickedness raged everywhere with impunity, murder and plunder in all directions". The missionaries, despite being harassed during the chaos, escaped harm thanks to the protection given to them by the wife of Naitō Okimori, who was friendly to the Christians. Much was lost when the Ōuchi manor was sacked, including the family archives, countless artifacts, and documents of court rites brought from Kyoto by the courtiers anticipating the move of the capital. (Even the cranes in the Ōuchi household garden were butchered.) Despite efforts at rebuilding, the city was burned again in 1557 and 1569 in the warfare between the Mōri and the Ōuchi claimants, such that in a space of thirty years after the coup, "no sign of its earlier prosperity remained".The downfall of the Ōuchi had far-reaching consequence beyond western Honshu. Since the courtiers in Yamaguchi were slaughtered, the imperial court in Kyoto became at the mercy of Miyoshi Nagayoshi. Warriors across Japan no longer ruled through the court but only used it to confer legitimacy. The once-peaceful Ōuchi territories in northern Kyushu descended into warfare among the Ōtomo, the Shimazu, and the Ryūzōji, who struggled to fill the void. The Ōtomo came to control much of these former Ōuchi domains in northern Kyushu, and their city of Funai flourished as a new centre of trade after the fall of Yamaguchi. At sea, foreign trade with China also suffered. The Ōuchi had been the official handlers of the Japan-China trade, but the Ming Chinese refused to acknowledge the usurpers and cut off all official trade between the two countries. Clandestine trade and piracy replaced the official trade of the Ōuchi, as the Ōtomo, the Sagara, and the Shimazu vied with each other to send ships to China. In the end, it was the Portuguese traders, with their near exclusive access to the Chinese market, who became the most successful intermediaries of the Japan–China trade for the rest of the 16th century.