The Ayukai were descended from Fujiwara Yasuchika, a grandson of Fujiwara Yamakage (824-888). They settled at Yokogoshi in Mutsu province and adopted that name, later moving to Ayukai. In 1587 Ayukai castle fell as the result of a war between the Date and Mogami, and the second son of Ayukai Moritsugu (1555-1624) became a retainer of Date Masamune. The Ayukai remained Date retainers until the Meiji Restoration.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005