Lifespan: Unknown to third month of Eiroku 10 (1567)
Title: Assistant Master of the Eastern Capital Office
Lord: Mōri Motonari → Mōri Takamoto
Father: Akagawa Fusanobu
Siblings: Motomitsu, Narihide, Motoyasu, Motohisa
Adopted Children: Matasaburō
Akagawa Motoyasu served as a retainer of the Mōri clan of Aki Province. The Akagawa clan were a branch of the Kobayakawa descended from the Dohi and Kanmu-Taira clans.
Motoyasu was the third son of Akagawa Fusanobu. In 1523, upon the death of Mōri Kōmatsumaru, Motoyasu was one of a group of fifteen elders (including his older brother, Akagawa Narihide) appealing for Mōri Motonari to become the successor as head of the Mōri clan. In 1532, a group of thirty-two retainers (including Motoyasu) added their individual seals to a written appeal to Motonari for a reconciliation of interests.
In 1550, following adoption of the political organ of Five Commissioners, Motoyasu was appointed as the head of the commissioners directly serving Mōri Takamoto, the eldest son of Morinari. While serving as a senior retainer of Takamoto, he frequently clashed with others in a faction close to Takamori, including Kodama Naritada and Katsura Mototada.
In 1563, Takamoto suddenly died following a festive dinner reception hosted by Wachi Masaharu, a retainer of the Mōri and head of the Wachi clan. The incident occurred in Sasabe in the Takata District of Aki Province. Motonari believed that Motoyasu had plotted the attack and sought to hold him responsible. Motoyasu, together with his younger brother (Motohisa), and adopted son (Matasaburō), were imprisoned. Four years later, in 1567, Motoyasu killed himself.
Following his death, it became known that Motoyasu had opposed Takamoto attending the reception and he was proved innocent of the killing. Motonari regretted the actions taken against Motoyasu, and thereafter enabled Motomichi Akamatsu, the second son of Motoyasu’s older brother, Narihide, along with his nephew, Motoyuki, to revive the Akamatsu clan.