Ikkō-ikki (一向一揆, "Ikkō-shū Uprising") were mobs of peasant farmers, Buddhist monks, Shinto priests and local nobles who rose up against daimyō rule in 15th- and 16th-century Japan. They followed the beliefs of the Jōdo Shinshū (True Pure Land) sect of Buddhism, which taught that all believers are equally saved by Amida Buddha's grace. They were organized to only a small degree; if any single person could be said to have had any influence over them it was Rennyo, the leader of the Jōdo Shinshū Hongan-ji sect at that time. Rennyo's attitude to the Ikkō-ikki was, however, highly ambivalent and pragmatic. Whilst he may have used the religious fervour of the Ikkō-ikki in the defence of his temple settlements, he was also careful to distance himself from the wider social rebellion of the Ikkō movement as a whole, and from offensive violence in particular.
According to Sansom, "The Ikko (Single-Minded) sect of Nenbutsu, or Buddha-calling ... is a branch of the worship of Amida developed from the teaching of Shinran into an aggressive doctrine of salvation by faith." In the 13th century, the jizamurai, a new class of small landowners, "formed leagues (ikki) for mutual defence", since they came from "good warrior families, long established in their own districts, and they were determined to protect their interests, both economic and social, against newcomers," according to Sansom The Shirahata-Ikki, "White Flag Uprising", and Mikazuki-Ikki, "Crescent Uprising", where examples of the numerous risings against the Ashikaga shogunate. An uprising involving an entire province was called a Kuni-Ikki (kuni meaning province). Uprisings took place in 1351, 1353, 1369, 1377, 1384–86, and 1366–69. The risings in the 15th century, Tsuchi-Ikki or Do-Ikki, were better organized "and the peasants appear to have played a more prominent part". At the conclusion of the Ōnin War, in 1477, "many of the members of the numerous ikki" occupied the monasteries and shrines, and "would ring the warning bells day and night, hoping to terrify the rich citizens," according to Sansom.
The Ikkō-ikki were, at first, disparate and disorganized followers of Rennyo's teachings. His missionary work, and his appointment to the position of abbot of the Kyoto Hongan-ji, was in 1457, allowed him to "express in words and deeds" his unorthodox views. In 1465, Rennyo was forced to flee Kyoto, and established a new Hongan-ji branch temple, Yoshizaki-gobō, in Echizen Province in 1471. It was at this temple that he began to attract a significant following among peasants and farmers. About 1486 brought the first violent uprising, the first major organized action on the part of the Ikkō-ikki. They overthrew the governor of Kaga Province, and took control of it for themselves; this represented the first time in Japanese history that a group of commoners ruled a province.
The Ikko-ikki fought Asakura Norikage in the Battle of Kuzuryūgawa of 1506 and defeated Nagao Tamekage in the 1536 Battle of Sendanno. They fought Asakura Norikage again in the 1555 Battle of Daishoji-omote.
Rennyo was a pacifist and taught pacifism. He advocated self-defense only as a guard against the particularly tumultuous times in which he lived. Daimyō, samurai warlords, fought one another for territory nearly constantly, across the entire country. Rennyo thus saw to it that the temples of his sect were fortified and defended from attackers. Though it was his charismatic leadership and populist teachings that inspired the fervor which powered the Ikkō-ikki uprisings, he never advocated or supported them. The uprisings continued nevertheless, past Rennyo's death in 1499, and the sub-sect of Jōdo Shinshū that he had founded spread as well. They established themselves in fortresses at Ishiyama Hongan-ji, just outside Osaka, and in Nagashima, on the borders of Owari and Ise Provinces and in a series of temples in Mikawa Province as well.
Towards the end of the 16th century, however, their growing numbers and strength caught the attention and concern of the great samurai leaders of the time. Tokugawa Ieyasu worried that sōhei of Mikawa Province would rise up and seize the province. In 1564, his forces, with the help of Jōdo-shū sōhei, defeated the Mikawa Ikkō-ikki in the Battle of Azukizaka.
The ikki attracted the ire of the likes of Tokugawa Ieyasu and Oda Nobunaga due to the economic and political threat they posed, more so than as a result of their military might. The Ishiyama Hongan-ji and other strongholds of the ikki lay across major trade routes and occupied the same areas that Nobunaga saw as his primary territorial objectives. Nearly every road to the capital from this western part of the country was controlled by the ikki or their allies, and the populist roots of the ikki movement gave them significant economic power as well. Nobunaga in particular sought the destruction of the Ikkō-ikki for these reasons, and because they allied themselves with nearly every one of his major enemies or rivals. Ashikaga Yoshiaki was once strongly supported in his claim to become Shogun by Nobunaga, but turned to the ikki when their relationship soured. The ikki also had powerful allies in the Mōri, Azai, and Asakura clans. The Ishiyama Hongan-ji and Nagashima fortresses were therefore besieged and destroyed by the forces of Oda Nobunaga. After several failed attempts at seizing each emplacement, he eventually succeeded.
In the 1580s, the last of the Ikkō-ikki courted Toyotomi Hideyoshi, and fought alongside his forces against warrior monks of other sects.
The Ikkō-ikki bands of the 16th century, due largely to their origins as countryside mobs, used quite varied armor and armament. Many wore the more traditional monk robes, with varying degrees and types of armor. Some wore various sorts of helmets, while others opted for the straw hat and cloak of a peasant. Naginata remained very common, along with a variety of swords and daggers, and a limited number of arquebuses. Finally, while not truly armor nor armament, a very common item wielded by the mobs of Ikkō-ikki monk warriors was a banner with a Buddhist slogan written upon it. Some of the more common slogans included the nenbutsu chant "Hail to Buddha Amida!" (Namu Amida Butsu; 南無阿弥陀仏) and "He who advances is sure of salvation, but he who retreats will go to hell".
Shin Buddhism was persecuted in response to the Ikkō-ikki, which caused the formation of kakure nenbutsu secret societies.Dobbins, James C. (1989). Jodo Shinshu: Shin Buddhism in Medieval Japan. Bloomington, Indiana: Indiana University Press. ISBN 9780253331861; OCLC 470742039
Neil McMullin (1984). Buddhism and the State in Sixteenth-Century Japan, Princeton University Press.
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