During the Sengoku period, while the conflict with the Wakasa-Takeda clan continued, rebellions and gekokujo (upheavals wherein the inferior defeats the superior) frequently occurred in the area, whereby the power of the Isshiki clan became further weakened.
戦国時代(日本)に入ると、若狭の武田氏と抗争を続く一方で、国内においても反乱・下克上が続発し、さらに一色氏の勢力は衰退してしまう。