Imagawa Yoshimoto
Imagawa Yoshimoto was a long-time opponent of Nobunaga's father, and had sought to expand his domain into Oda territory in Owari. In 1560, Imagawa Yoshimoto gathered an army of 25,000 men, and started his march toward the capital city of Kyoto, with the pretext of aiding the frail Ashikaga Shogunate. The Matsudaira clan also joined Yoshimoto's forces. The Imagawa forces quickly overran the border fortresses of Washizu and Matsudaira forces led by Matsudaira Motoyasu took Marune Fortress. Against this, the Oda clan could rally an army of only 2,000 to 3,000 men. Some of his advisors suggested "to stand a siege at Kiyosu" but Nobunaga refused, stating that "only a strong offensive policy could make up for the superior numbers of the enemy", and calmly ordered a counterattack against Yoshimoto.