The two were fought during Oda Nobunaga's attempted sieges of the Ishiyama Hongan-ji in Osaka. The Hongan-ji was the primary fortress of the Ikkō-ikki, mobs of warrior monks, priests, and farmers who opposed Oda's rule. He ordered one of his admirals, Kuki Yoshitaka, to organize a blockade against the fleets of the Ikki's allies, who sought to supply the fortress and break the siege. Many of the ruling families of the neighboring provinces opposed Oda, chief among them Mōri Terumoto of the Mōri clan.
First battle (1576)
In the first battle, in 1576, the Mōri navy led by Motoyoshi, son of Murakami Takeyoshi, defeated Kuki Yoshitaka's fleet, breaking the blockade and supplying the fortress.
The Mōri navy departed Iwaya on Awaji Island on July 12, crossed over to Kaizuka in Senshu, and, after agreeing with the Saiga sect of Kishu, proceeded from Sakaitsu to the mouth of the Kizu River on the 13th. There, they encountered the Oda navy, consisting of several large ships with built-up wells and over 200 guard ships, and a battle ensued. The battle took place from the 13th to the early morning of the 14th, and the Mōri navy defeated the Oda forces, burning down all of the large ships.
On July 15 (according to the Shinchō Koki), when the Mōri navy attempted to deliver military supplies to Ishiyama Hongan-ji Temple, the Oda navy attempted to intercept them at the mouth of the Kizu River, but their ships were set on fire with Bō-hiya incendiary weapons.
Second battle (1578)
In 1578 around June, Kuki Yoshitaka built six Atakebune ships equipped with large guns and three cannons at the bay of Ise.