Jōdo Shinshū in the context of "Enryaku-ji"

Ikkō-ikki (一向一揆; "single-minded leagues") were armed military leagues that formed in several regions of Japan in the 15th–16th centuries, composed entirely of members of the Jōdo Shinshū sect of Buddhism. In the early phases, these ikki leagues opposed the rule of local governors or daimyō, but over time as their power consolidated and grew, they courted alliances with powerful figures in the waning Ashikaga shogunate until they were crushed by Oda Nobunaga in the 1580s.

The Ikkō-ikki mainly consisted of priests, peasants, merchants and local military rulers who followed the sect, but they sometimes associated with non-followers of the sect. They were at first organized to only a small degree. However, during the reforms of the monshu Jitsunyo, and further under his grandson Shōnyo, the temple network enabled more efficient and effective mobilization of troops when needed. The relationship between Hongan-ji and its monshu was complicated: some monshu, such as Rennyo, condemned the violence, others, such as Shōnyo and Kennyo, channelled it to further political aims.

Ikkō-shū (一向宗) or "single-minded school" is usually viewed as a small, militant offshoot from Jōdo Shinshū Buddhism, though the name has a complex history.

Originally, Ikkō-shū was an "obscure band of Pure Land proponents" founded by Ikkō Shunjō in the fifteenth century. He was a disciple of Ryōchū of the Chinzei branch of Jōdo-shū Buddhism and similar to Ippen's Ji-shū. However, when the religious and military-political establishment began to crack down on the Nembutsu, little distinction was made between the various factions. Most of Ikkō Shunjo's followers therefore defected to the more powerful Jōdo Shinshū and the name Ikkō-shū ultimately became synonymous with Jōdo Shinshū.

The Monshu (門主 or 門首), or keeper of the gate is a term used to Jōdo Shinshū Buddhism that refers to the spiritual leader of either the Nishi Hongan-ji branch, or the Higashi Hongan-ji branch. Traditionally these monshu were direct descendants of the founder Shinran and thus part of the Ōtani family.

Different kanji are used for the term through pronunciation is the same: 門主 by Nishi Honganji, and 門首 by Higashi Honganji.

Hongan-ji (本願寺, Temple of the Primal Vow), also archaically romanized as Hongwanji, is the collective name of the largest school of Jōdo Shinshū Buddhism, which further sub-divides into the Nishi (Western) and Higashi (Eastern) branches. 'Hongan-ji' may also refer to any one of several actual temple buildings associated with the sect. Nishi Honganji (西本願寺) and Higashi Honganji (東本願寺) are two major temples in Kyoto.

Rennyo (蓮如, 1415–1499) was the 8th Monshu (Patriarch) of the Hongan-ji Temple of the Jōdo Shinshū sect of Buddhism, and descendant of founder Shinran. Jodo Shinshu Buddhists often referred to him as the restorer of the sect (Chūkō no sō (中興の祖) in Japanese). He was also known as Shinshō-in (信証院), and posthumously Etō Daishi (慧灯大師). During the conflict and welter of the Ōnin War and the subsequent warfare (Sengoku era) that spread throughout Japan, Rennyo was able to unite most of the disparate factions of the Jodo Shinshu sect under the Hongan-ji, reform existing liturgy and practices, and broaden support among different classes of society. Through Rennyo's efforts, Jodo Shinshu grew to become the largest, most influential Buddhist sect in Japan.

Rennyo is venerated along with Shinran, and liturgical reforms he implemented are still in use today in Jodo Shinshu temples. Further, Rennyo's letters were compiled and are still recited in Jodo Shinshu liturgy.

Jōdo-shū (浄土宗, "The Pure Land School") is a Japanese branch of Pure Land Buddhism derived from the teachings of the Kamakura era monk Hōnen (1133–1212). The school is traditionally considered as having been established in 1175 and is the most widely practiced branch of Buddhism in Japan, along with Jōdo Shinshū. There are various branches of Jōdo-shū, which the largest and most influential ones being Chinzei-ha and Seizan-ha.

Jōdo-shū Buddhism focuses exclusively on devotion to Amitābha Buddha (Amida Nyorai), and its practice is focused on the Nembutsu (recitation of Amitābha’s name). As in other forms of Pure Land Buddhism, adherents believe that the faithful recitation of the phrase "Namu Amida Butsu" (Homage to Amida Buddha) results in birth in the pure land of Sukhavati.

Shinran (親鸞; Japanese pronunciation: [ɕiꜜn.ɾaɴ], May 21, 1173 – January 16, 1263) was a key Japanese Buddhist figure of the Kamakura Period who is regarded as the founder of the Jōdo Shinshū school of Japanese Buddhism. A pupil of Hōnen, the founder of the Japanese Pure Land movement, Shinran articulated a distinctive Pure Land vision that emphasized faith and absolute reliance on Amida Buddha’s other-power.

While Shinran trained as a Tendai monk on Mount Hiei, he lived much of his life as a married Buddhist teacher unlike other Kamakura Buddhist reformers, and he described himself as "neither monk nor layman". Shinran's major work, the Kyōgyōshinshō (Teaching, Practice, Faith, and Realization), is a systematic exposition and defense of Pure Land doctrine. Shinran taught that liberation arises from the entrusting mind (shinjin) awakened through Amida's compassionate power, not from any merit or power of one's own. His interpretation profoundly reshaped the course of Japanese Buddhism and continues to influence East Asian religious thought.

Shinjin (信心) is a central concept in Japanese Pure Land Buddhism which indicates a state of mind which totally entrusts oneself to Amida Buddha's other-power (Japanese: tariki), having utterly abandoned any form of self effort (jiriki) or calculation (hakarai). The term has been variously translated as "faith", "entrusting heart", "true entrusting", "mind of true faith", and so on. It is also often left untranslated in English language publications on Shin Buddhism. It is a key concept in the thought of Shinran (1173–1263), the founder of Jōdo Shinshū. Shinran's concept of shinjin is rooted in the concept of faith found in Indian Pure Land scriptures and in the teachings of the Chinese Pure Land Buddhist masters Tanluan and Shandao, who also emphasized the importance of faith in Amitābha Buddha.

The term Shinjin (Chinese: Xìnxīn) is also used in other Buddhist traditions occasionally, though not as commonly as in Pure Land. The influential early Chan Buddhist poem Xìnxīn Míng (Faith-Mind Inscription) is one example.

Tendai (天台宗, Tendai-shū), also known as the Tendai Dharma Flower School (天台法華宗, Tendai hokke shū, sometimes just Hokkeshū), is a Mahāyāna Buddhist tradition with significant esoteric elements that was officially established in Japan in 806 by the Japanese monk Saichō. The Tendai school, which has been based on Mount Hiei since its inception, rose to prominence during the Heian period (794–1185). It gradually eclipsed the powerful Hossō school and competed with the rival Shingon school to become the most influential sect at the Imperial court.

By the Kamakura period (1185–1333), Tendai had become one of the dominant forms of Japanese Buddhism, with numerous temples and vast landholdings. During the Kamakura period, various monks left Tendai to found new Buddhist schools such as Jōdo-shū, Jōdo Shinshū, Nichiren-shū and Sōtō Zen. The destruction of the head temple of Enryaku-ji by Oda Nobunaga in 1571, as well as the geographic shift of the capital away from Kyoto to Edo, ended Tendai's dominance, though it remained influential.