Although Yoshimoto challenged Nobuhide to a decisive battle in 1542 by counting on an alliance with various local ruling families in Mikawa Province, he was defeated by Nobuhide's intensive attack (the First Battle of Azuki-zaka).
このため、義元は三河の諸豪族と連合して天文11年（1542年）に信秀と一大決戦に臨むが、その猛攻の前に敗れた（第1次小豆坂の戦い）。