Ishiyama Honganji War Timeline (1570–1580)

Kennyo issues a manifesto declaring Nobunaga an enemy of Buddhism and launches a sudden attack on Oda forces at Settsu Fukushima.

The Honganji army fights Oda troops along the Yodo River but retreats back into the fortress.

Nobunaga, already fighting the Asai, Asakura, and Miyoshi, accepts an Imperial Court–brokered truce. The first rising lasts less than a month.

This period becomes a shifting, grinding conflict rather than a static siege.

Kennyo secretly forms alliances with Takeda Shingen and the Mori clan to pressure Nobunaga from east and west.

Ikko-ikki uprisings erupt across Nagashima (Ise), Echizen, and Kaga, forcing Nobunaga to fight a broad religious network rather than a single fortress.

Realizing how costly a direct assault would be, Nobunaga’s forces constructed a ring of ten strategic forts—including Tennoji and Mitsumatsu—to choke off the land routes to the Ishiyama Honganji. Faced with a slow death by starvation, the Ikko-ikki launched a massive breakout attempt to shatter this encirclement.

The conflict began when 15,000 defenders surged out of the fortress to assault the Oda siege lines. They successfully pinned down the Oda vanguard under Akechi Mitsuhide and Araki Murashige, threatening to collapse the entire blockade.

Nobunaga reinforced from Kyoto with only 3,000 men. Despite being outnumbered, he ignored the caution of his generals and personally led a charge to relieve his besieged forts.

The ferocity of the Oda counter-attack pushed the warrior-monks back to their gates, but the victory came at a high cost. Nobunaga was wounded by an arquebus shot to the leg, a rare moment of physical vulnerability.

Despite the land success, the strategic victory was snatched away by the sea. The Mori clan’s fleet arrived, smashing through the Oda blockade at the mouth of the Kizugawa River.

This naval breakthrough resupplied the fortress with food and ammunition, effectively nullifying Nobunaga's land gains and forcing an Oda withdrawal. It was a rare, humbling setback that ensured the Honganji would endure for years to come.

The Ishiyama Honganji was a nearly invulnerable fortress; as long as the Mori navy could ferry supplies through the Inland Sea, the monks could hold out indefinitely. Nobunaga realized that to win the war, he had to win the water.

In the first battle of Kizugawaguchi (1576), the Mori navy’s superior numbers and traditional tactics overwhelmed the Oda fleet, keeping the Honganji's lifeline open.

In response, Nobunaga commissioned the shipwright Kuki Yoshitaka to build six massive iron-armored atakebune. These were essentially the world's first "ironclads"—gigantic wooden warships reinforced with iron plates to deflect fire arrows and incendiary weapons.

Nobunaga's return match in 1578 was a massacre. The iron-plated vessels proved impervious to the Mori fleet's incendiary tactics. The Oda ships systematically crushed the opposition, permanently severing the sea routes to the Honganji.

Without their naval lifeline, the fortress was finally isolated, beginning the slow countdown to its eventual surrender.

With the sea route closed, the Ikki begin to starve.

Shimozuma Nakayuki leads repeated sallies from the fortress, but ammunition and food run out.

By April 1580, the defenders are exhausted and isolated — yet the fortress still has not fallen by force.

Nobunaga negotiates the surrender of Ishiyama Honganji through the Imperial Court, giving Kennyo Kosa an honorable exit.

Once evacuated, the entire Ishiyama Honganji complex burns to the ground.

The fortress is never conquered — it is abandoned, then destroyed.