Lifespan: Kyōroku 1 (1528) to 5/9 of Eiroku 7 (1564)
Title: Governor of Settsu
Father: Miyoshi Motonaga
Adoptive Father: Atagi Haruoki
Siblings: Miyoshi Nagayoshi, Miyoshi Jikkyū, Fuyuyasu, Sogō Kazumasa, Noguchi Fuyunaga
Children: Jintarō (Nobuyasu?), Kiyoyasu (?)
Atagi Fuyuyasu served as a retainer of the Miyoshi clan. He was the third son of Miyoshi Motonaga and adopted by the Atagi clan. Fuyuyasu served as captain of the Awaji Navy in support of the Miyoshi governance, but was killed by his eldest brother, Miyoshi Nagayoshi. There are many views and uncertainties regarding the reasons for the incident.
Fuyuyasu’s father, Motonaga, reached a settlement with Hosokawa Harumoto, in 1531, only to be killed the following year by monks acting in concert with Harumoto’s rival, Hosokawa Takakuni. Harumoto served as a sengoku daimyō and kanrei, or deputy shōgun, to Ashikaga Yoshiharu. Harumoto was the final kanrei of the Muromachi period to exercise real authority.
The Atagi clan served as the navy for Awaji Province. His older brother, Nagayoshi, was driven out of the Kinai and went to the island province of Awaji. Nagayoshi arranged for Fuyuyasu to be adopted by Atagi Haruoki, lord of the Atagi clan, and to become his successor.
On behalf of the Miyoshi clan, Nagayoshi led soldiers on battles in Settsu, Kawachi, and Izumi provinces. Fuyuyasu’s next eldest brother, Miyoshi Jikkyū, operated in Awa Province. Fuyuyasu served in Awaji, and his younger brother, Sogō Kazumasa, in Sanuki Province. Fuyuyasu participated in suppression actions near Ōsaka Bay, the Battle of Kitashirakawa against Hosokawa Harumoto in 1558, and the Battle of Kumeda against Hatakeyama Takamasa in 1562, causing the loss of his brother, Jikkyū. Fuyuyasu retreated to Awa, and just months later, prevailed against Takamasa at the Battle of the Kōkyō Temple in the Takayasu District of Kawachi Province.
Thereafter, Kazumasa, Jikkyū, and Miyoshi Yoshioki (Nagayoshi’s eldest son and Fuyuyasu’s nephew), all died in succession. Fuyuyasu made great efforts supporting Nagayoshi in a bid for survival of the Miyoshi family. Nevertheless, in 1564, Fuyuyasu was summoned to Iimoriyama Castle and forced to kill himself at the age of thirty-eight. His son, Atagi Nobuyasu, became his successor.
Circumstances for the killing
The details and circumstances of Fuyuyasu’s killing are the subject of an assortment of theories.
Yamashina Tokitsugu, a noble of the Court and contemporary of Fuyuyasu, noted in his diary that Fuyuyasu was killed as a result of his own treachery.
Meanwhile, many believed without doubt that the killing was orchestrated by Matsunaga Hisahide. Certain sources cite retribution for slander against Hisahide as definitely the reason, specifically, that Hisahide had informed Nagayoshi that Hisahide was planning a rebellion as an act of betrayal. In fact, following the successive deaths of Kazumasa, Jikkyū, and Yoshioki, Fuyuyasu was the only remaining member of the Miyoshi family with authority on a par with or above that of Hisahide, and it would not be beyond reason for Hisahide to consider eliminating Fuyuyasu as a means to take control of the family. Other sources cite retribution for slander as the basis for the killing, without specifically identifying Hisahide as the perpetrator.
Another view is that Nagayoshi killed Fuyuyasu on his own accord. Following the deaths of Kazumasa, Jikkyū, and Yoshioki, Fuyuyasu was the sole remaining influential family member under Nagayoshi. Fuyuyasu’s considerate nature made him popular among retainers in the clan, a dynamic that may have caused friction and alienation from Nagayoshi with regard to plans for Nagayoshi’s adopted son, Yoshitsugu, as his designated successor. Or, even in the absence of ill-will, Nagayoshi may have decided to kill Fuyuyasu at that time to avoid a power-struggle in the future after Yoshitsugu was set to become his successor.
Alternatively, around the time of the incident, Nagayoshi may have had impeded judgment owing to serious illness. Upon later learning that Fuyuyasu had been innocent, he became severely depressed and delusional, dying shortly thereafter.
Finally, Nagayoshi may have purged Fuyuyasu, as witnessed in other precedents during the era such as between Ashikaga Takauji and Asahikaga Tadayoshi, or Toyotomi Hideyoshi and Toyotomi Hidetsugu. A poor relationship between Nagayoshi and Fuyuyasu could have served as a preamble to the ensuing finale of the Miyoshi’s governance.