[1][2] Oda Nobuhide, a daimyo with significant influence in southern Owari, died on April 8, 1551, after a short contagious illness.

His heir, Oda Nobunaga, who was barely 18 at the time, inherited a large feudal domain around Nagoya Castle, but he enjoyed generally bad reputation amongst the people of Owari for his eccentric and rude public behavior.

He also showed complete disdain for formal clothing and proper social behavior of a lord, wearing sleeveless bathrobe and short trousers tied with hemp rope in public, eating melons while riding backwards on his horse and often dancing in female clothing in taverns, gaining the nickname The Fool of Owari.

[1][2] In early of 1552, barely several month after his father's death, one of Nobunaga's senior retainers, Yamaguchi Noritsugu, the castellan of Narumi Castle, and his son Yamaguchi Kurojiro (Noriyoshi) defected to the powerful Imagawa clan of Suruga (who controlled neighbor eastern provinces of Mikawa and Totomi) and invited their troops to Owari, who made several fortifications on Oda land.

After two hours of intense fighting, Nobunaga lost some 30 samurai, and retreated the same day back to Nagoya, leaving contested lands in eastern Owari under Imagawa control.