He is thought to have been born in Suō Province into the Toida family, senior retainers of the Ōuchi. His mother seems to have come from the Sue family, and because Sue Okifusa's own son died young, he, as Okifusa's nephew, was adopted into the Sue house. The Sue were a distinguished family who served for generations as deputy shugo of Suō.
As a boy he was known as a handsome youth and served close to his lord Ōuchi Yoshitaka, who was very fond of him. At his coming of age he received a character from Yoshitaka's name and was called Takafusa. By the following year he had inherited the family headship from his adoptive father Okifusa, becoming a senior pillar of the Ōuchi house while still young.
When Amago Haruhisa of Izumo attacked Mōri Motonari's Yoshida-Kōriyama castle in Aki with a large army, Takafusa was made commander in chief by Yoshitaka and went to its relief. Fighting together with Motonari, he drove off the Amago army early this year. The young commander's fame rose greatly, and from this time he became closely involved with Motonari.
Riding his momentum, he attacked the Amago stronghold of Gassan Toda Castle in Izumo, but failed to take it and suffered a great defeat, losing many men including Yoshitaka's adopted son Harumochi. It is said that during the retreat he gave his own rations to his guards and staved off hunger himself by eating dried fish.
After the defeat Yoshitaka lost interest in war and turned his heart to culture such as poetry and learning. Amid this, Sagara Taketō, skilled in documents and ceremony, rose to favor and clashed bitterly with Takafusa, who valued martial strength. This year Takafusa once forced Taketō into retirement and regained leadership within the house.
On Yoshitaka's orders he campaigned in Bingo, attacking Kannabe Castle with Mōri Motonari and others, and continued to serve as a commander. But this year, when Sagara Taketō was recalled by Yoshitaka to a high post, Takafusa was again removed from the center of the house. The gulf between him and Yoshitaka gradually deepened.
He plotted with Naitō Okimori and others to kill Sagara Taketō, but the plan was discovered, and questioned by Yoshitaka he lost his standing. Around the same time, seeing a change of headship in the Ōtomo clan of Bungo, Takafusa is said to have settled on a plan to remove Yoshitaka and bring in Haruhide, younger brother of Ōtomo Yoshishige (later Sōrin), as head of the Ōuchi.
When Taketō, fearing for his life, fled Suō, Takafusa raised troops and attacked Yamaguchi. Yoshitaka fled to the Taineiji temple in Nagato, where he took his own life. This was the Taineiji Incident. The fall of the head of the Ōuchi, unrivaled in western Japan, at the hands of a retainer became a symbol of the age of gekokujō.
He welcomed Ōtomo Haruhide to Suō and set him up as the new head of the Ōuchi, while seizing real power over the house himself. To show inside and outside that he had accepted a new lord, he received a character from Haruhide's name and changed his name to Harukata. Haruhide later took the name Ōuchi Yoshinaga, while Harukata ran politics and war.
Harukata strengthened his forces to tighten control of the house, but many lords resented it. Yoshimi Masayori of Iwami rose against him, and while Harukata marched to subdue him, Mōri Motonari of Aki also left the Ōuchi side and seized castle after castle. The army Harukata sent was defeated at the Battle of Oshikibata, and Aki fell into Mōri hands.
Harukata crossed to Itsukushima in Aki with an army said to number twenty or thirty thousand and attacked the Mōri's Miyao Castle. But surprised by Mōri troops who had landed on a stormy night, he was defeated and, his retreat cut off, took his own life on the island. His farewell poem, beginning "What should I regret, what should I resent," has been handed down.
Hōjō UjiyasuImagawa YoshimotoImai SōkyūTakeda ShingenSen no RikyūShibata KatsuieMiyoshi NagayoshiTakigawa Kazumasu
People of the Sengoku/Azuchi-Momoyama period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.