Sieges of Nagashima

What Happened

The Sieges of Nagashima were three separate assaults by Oda Nobunaga on a network of fortified river islands in Owari Province, held by the Ikkō-ikki, a militant Buddhist movement. The first attack came in 1570, the second in 1573, and the third in 1574. Nobunaga lost commanders in the early attempts and only destroyed the complex on the final campaign.

The Nagashima defences were not a single castle. They were a string of forts and stockades built across the delta where several rivers met, with the Ganshō-ji monastery at their centre. The Ikkō-ikki had earlier taken Nagashima Castle and folded it into this defensive line. Water and marshland made the position difficult for a conventional army to approach.

The campaign ended on 13 October 1574, when the last Ikkō-ikki strongholds at Nagashima fell. The complex was destroyed.

Background

The Ikkō-ikki were leagues of warrior-monks, local samurai, and peasants bound together by the Jōdo Shinshū school of Buddhism. Their name means "single-minded league" — ikki refers to an uprising or league, and Ikkō to their single-minded devotion. They governed several regions of Japan as autonomous religious communities, collecting taxes and fielding armies.

Oda Nobunaga was a daimyo (大名, daimyō, a regional warlord) based in Owari Province, on Japan's Pacific coast. Through the 1560s he expanded his territory and moved toward national dominance. The Ikkō-ikki stood directly in his path, both geographically and politically: they answered to a religious authority rather than to any warlord.

Nagashima sits in Owari, Nobunaga's home province. The Ikkō-ikki presence there was a permanent threat inside his own territory. Their main fortress, Ishiyama Hongan-ji, was a vast temple-fortress that Nobunaga would besiege for eleven years, and the Nagashima sieges ran concurrently with that longer campaign. The fighting belongs to the Sengoku period, the century of civil war, and the opening year of the Genki era (元亀, Genki, a Japanese era name).

Why It Mattered

Nagashima showed that the Ikkō-ikki could not be brushed aside. Nobunaga attacked in 1570 and again in 1573 without breaking them, and the first campaign cost him commanders. The Ikkō-ikki were, by the reckoning of the time, among his most dangerous opponents — not a minor sect but a military power with fortifications, manpower, and a network stretching across several provinces.

Destroying Nagashima in 1574 removed an enemy enclave from Owari itself. It also demonstrated Nobunaga's method against religious resistance: prolonged assault ending in annihilation rather than negotiated submission. The lesson carried into the larger war against Ishiyama Hongan-ji.

The sieges belong to the broader Ishiyama Hongan-ji War, Nobunaga's long struggle with the Jōdo Shinshū movement. That conflict shaped the relationship between military power and organised religion in late sixteenth-century Japan, and the outcome at Nagashima was one of its decisive local results.

The Name in Japanese

The Japanese name is 長島一向一揆, read in kana as ながしまいっこういっき, romanised as Nagashima Ikkō-ikki.

Breaking it down:

長 — read naga here. It means "long."

島 — read shima here. It means "island." Together, 長島 (Nagashima, "long island") is the place name: the river-island district in Owari Province where the fortresses stood. The same two characters can also be read chōtō in other contexts, but as a place name the reading is Nagashima.

一 — read ik here, from ichi. It means "one." The sound shifts to ik because of the consonant that follows.

向 — read kō here, from muku / mukau, "to face" or "to direct oneself toward." In this compound it carries the sense of aiming single-mindedly at one thing. Together, 一向 (ikkō) means "single-minded," "wholehearted," "of one direction."

一 — read ichi here. Again "one."

揆 — read ki. It means "plan," "measure," or "principle," and by extension a body of people acting on a shared purpose. 一揆 (ikki) means an uprising, a league, or a confederation — a group sworn to a common cause.

So the full name means roughly "the single-minded league of Nagashima." In Japanese historiography the term 一向一揆 (Ikkō-ikki) is the standard label for these Jōdo Shinshū militant communities and their revolts, and 長島一向一揆 specifies the Nagashima instance. English texts often render it "Sieges of Nagashima," but the Japanese name describes the movement and the place, not the military action.

Key Figures

Oda Nobunaga (織田信長) — the daimyo of Owari who led all three campaigns against Nagashima between 1570 and 1574. He was simultaneously conducting the long siege of Ishiyama Hongan-ji.

The Ikkō-ikki (一向一揆) — the single-minded leagues of Jōdo Shinshū adherents who held Nagashima and its river-island fortifications. They are the named participant force in the sieges.

Ikeda Tsuneoki (池田恒興) — a commander associated with the Nagashima fighting.

Gamō Ujisato (蒲生氏郷) — a commander associated with the Nagashima fighting.

Nagashima Castle (長島城) — the fortress the Ikkō-ikki had captured and incorporated into their defensive line around the Ganshō-ji monastery.