The conflict between Hongan-ji Temple and the Oda clan, which began in 1570 and lasted over ten years as the so-called Ishiyama War, burdened Nobunaga heavily, since Hongan-ji Temple had gained the upper hand through the coalition between Kennyo and others who had entrenched themselves in the fortified Ishiyama Honganji Temple, and Hongan-ji Temple followers who carried on a resistance movement against the Oda clan in various regions.
1570年から十年にわたって続いた本願寺と織田氏の抗争、いわゆる石山戦争は、要塞化された石山本願寺に立て篭もる顕如らと、各地で織田氏への抵抗運動を繰り広げる本願寺門徒との連携によって本願寺が優勢に立ち、信長を大いに苦しめることとなる。