Hongan-ji, also archaically romanized as Hongwanji, is the collective name of the largest school of Joudo Shinshuu Buddhism (which further sub-divides into the Nishi and Higashi branches). 'Hongan-ji' may also refer to any one of several actual temple buildings associated with the sect.
The Hongan-ji was established as a temple in 1321, on the site of the Otani Mausoleum, where Shinran, the founder of the Joudo Shinshuu (True Pure Land) sect was buried. The mausoleum was attended by Shinran's grandson (through daughter Kakushinni), Kakue. Kakue's own son, Kakunyo, became the first chief priest of the Hongan-ji and 3rd Monshu, and dedicated it to the worship of Amida Buddha. The Hongan-ji first gained power and importance in the 15th century, when Rennyo became its eighth chief priest, or Monshu. However, the Tendai sect, based on Mount Hiei, saw this expansion as a threat and attacked the Hongan-ji three times with their army of warrior monks. Rennyo fled to Yoshizaki, where he established a new temple compound.
During the Sengoku period, fearing the power of the monks of the Hongan-ji, Oda Nobunaga tried to destroy it. For ten years, he laid siege to the Ishiyama Hongan-ji in Osaka, one of the two primary temple fortresses of the sect.
In 1602, just after Tokugawa Ieyasu became Shogun, he declared that the Hongan-ji be split in two. Kyonyo, the 12th chief priest, or monshu, of Hongan-ji became the first of the new Higashi Honganji, or Eastern Temple of the Primal Vow, while his younger brother Junnyo became the 12th chief priest of the original Hompa-Honganji, or Western Temple of the Primal Vow, often called Nishi-Honganji.
Higashi Hongan-ji is one of two dominant sub-sects of Shin Buddhism in Japan and abroad, the other being Nishi Honganji.
During the Meiji Restoration in the 1860s, the government set down new guidelines for the management of religious organizations. An organization called Shinshuu Otani was put in control of the Higashi Hongan-ji. In 1987, this temple was renamed "Shinshuu Honbyou", or Shinshuu Mausoleum. While the temple is therefore, officially, no longer "Higashi Hongan-ji," most still regard it as such. The buildings have not been changed or moved, and of course the historical cultural and religious significance of the place cannot be changed.
Due to opposition to the creation of the Shinshuu Otani, and a number of other controversies and disputes, several new Higashi Hongan-ji branches came into existence such as the Higashiyama Honganji founded in Kyoto in 1996 by Otani Korin, and the Tokyo Higashi Honganji whose current leader is Otani Koken. Despite or perhaps even because of this climate of instability the Higashi Hongan-ji movement has also produced a significant number of controversial but influential thinkers, such as Soga Ryojin, Kiyozawa Manshi, Kaneko Daiei and Haya Akegarasu, amongst others.
The largest Higashi Hongan-ji grouping, the Shinshu Otaniha has approximately 5.5 million members, according to statistics.