In Japanese history, the siege of Ishiyama Hongan-ji — the main stronghold of the Ikkō-ikki movement during Oda Nobunaga’s campaign — is considered the longest, lasting from August 1570 to August 1580.
Initially, in 1496, the monk Rennyo (1415–1499), the ideological and spiritual leader of the Jōdo Shinshū Buddhist sect, withdrew to the mouth of the Yodo River and built a secluded hermitage on the ruins of the ancient Naniwa palace, on the "great slope" — Osaka. This modest retreat quickly grew into a large temple complex, and by 1532, after the destruction of Yamashina Mido, Ishiyama Hongan-ji had become the central fortress-monastery of the Ikkō-ikki, surrounded by the temple town (jinai-machi).
The monastery’s defenses were superbly designed: located on islands at the river’s mouth, surrounded by natural moats (channels) with bridges that could be quickly dismantled in case of attack. Defensive features included earthen ramparts (dorui) with palisades, moats (hori), Koraimon-style gates, and watchtowers. The surrounding jinai-machi acted as the outer perimeter, divided into wards by earthen walls (dobei) and moats. At the center was the island core, fortified with stone walls (ishigaki), dobei, yagura towers, and heavy yaguramon gates—closely resembling a fortified samurai castle.
Instead of a donjon, the central area housed two main halls—Amidado and Goeido—connected by a corridor. These architectural forms remain in use in modern Jōdo Shinshū temples.
The standing garrison consisted of about 100 monks, but at the toll of a bell, up to 10,000 lay followers (monto), including those from Kaga and Echizen provinces, could be summoned. The Mori clan’s navy actively supported the monastery, while Uesugi Kenshin and Takeda Shingen diverted Nobunaga’s forces in the northwest, slowing the siege.
In August 1570, Nobunaga, with a force of around 30,000, initiated the siege, surrounding the monastery with forts. In September, warrior-monks stormed the Kawaguchi and Takadono forts using 3,000 arquebusiers and coordinated volley fire.
The first years were intense, but sea routes kept the monastery supplied until 1576–1578, when Nobunaga shifted focus to maritime blockade using large ships and arquebusiers. After victories in the second Battle of Kizugawaguchi and the death of Uesugi Kenshin, Nobunaga entered the final phase: cutting off allies and capturing outer defenses.
In April 1580, abbot Kōsa (Kennyo) surrendered under imperial order, but the monastery was burned to prevent its capture. Its foundations were destroyed in August. Three years later, in 1583, Toyotomi Hideyoshi built Osaka Castle on the site.
Thus, the siege of Ishiyama Hongan-ji became the largest and longest fortress war in Japanese history, showcasing the defenders' caution and the besiegers’ persistence.
See also
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The Siege of Tihaya Castle
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The Siege of Akasaka Fort
Kusunoki Masashige, hero of the Genko Rebellion (1331–1333), was a talented commander and inventive strategist. The two sieges of castles where he acted as defender are inscribed in gold letters in the history of Japanese military art.
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The Battle of Itinotani
After the death of Minamoto no Yoshinaka, the Genpei War entered its final phase, which is closely associated with the name of Minamoto no Yoshitsune. On March 13, 1184, he and his brother Noriyori set out to accomplish what their cousin had failed to do: deliver a final defeat to the Taira.
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The Battle of Uji 1180
Minamoto no Yorimasa did not need a special pretext for his growing hostility toward the Taira clan to turn into open rebellion. The court also included the discontented Prince Motohito, the second son of the former Emperor Go-Shirakawa. He had already been passed over twice in the selection of the heir to the throne. The second time this happened was in 1180, when the young Antoku was enthroned. Thus, Kiyomori, the head of the Taira clan, became the emperor's grandfather.
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The Battle of Shigisan
The conflict between the Soga and Mononobe clans, who were related to the imperial dynasty, arose on religious grounds. The Soga supported Buddhism, which had come from Korea, while the Mononobe remained faithful to Shintoism and fiercely opposed the spread of “foreign teachings.” Tensions reached a peak after the death of Emperor Yomei in 587.
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The Mongol invasion of Japan
At the end of the 13th century, Japan faced a danger far more serious than any internal strife. In 1271, the Yuan dynasty, founded by Kublai Khan, grandson of Genghis Khan, established itself in China. His army was truly enormous: tens of thousands of soldiers — Chinese, Koreans, Jurchen, and especially Mongols, who had conquered the territory from Korea to Poland and from the northern taiga to Egypt. Only one country remained unconquered — Japan.
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The Genpei War
As early as the 8th century AD, Japanese emperors gradually lost their real power and became symbolic figures, under the complete control of the powerful Fujiwara clan. This clan, by marrying their daughters to emperors, effectively monopolized the government of the country: all key military and administrative positions were held by representatives of the Fujiwara.
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The Rebellion of Fujiwara no Hirotsugu
Fujiwara no Hirotsugu was the son of Fujiwara no Umakai, one of the most important court officials of the Nara period. By 740, the Fujiwara clan had held the reins of government for several decades. However, in 735–737, Japan suffered a severe trial: the country was hit by a devastating smallpox epidemic. It coincided with a series of crop failures, and together, disease and famine claimed the lives of about 40% of the population of the Japanese islands. The consequences were particularly tragic for the aristocracy. The mortality rate among the court nobility exceeded that among the common people. All four Fujiwara brothers, who held the most important positions at court — Umakai, Maro, Mutimaro, and Fusasaki — died.
