is a sect of Japanese Buddhism that integrates the pratimoksha rules, the ordination precepts of Early Buddhism, and the samaya rules of Vajrayana, all grounded in Shingon Buddhism's esoteric doctrine. It is noted for reviving the spirit of the Risshà « sect, one of the Six Schools of Nara Buddhism (Ã¥ÂÂé½å Âå®Â).
The sect emphasizes adherence to the vinayaâÂÂthe Buddhist monastic disciplineâÂÂmore than traditional Shingon Buddhism, while retaining tantric practices. Its home temple is Saidai-ji in Nara City.
The sect was founded in the 13th century by the monk Eison (å¡å°Â; also known as Kosho Bosatsu), a disciple of Jà Âkei. Eison held Kà «kai (the founder of Shingon Buddhism) in high reverence and established a synthesis between the Shingon and Risshu traditions. His efforts were continued by his eminent disciple Ninshà  (å¿Âæ§; also called Ninsei).
Reacting to the decline in monastic discipline, Eison and Ritsu monk Kakumori began personally administering the ordination precepts, bypassing the imperial state's monopoly on ordination procedures (èªèªÂÃ¥ÂÂæÂÂ, jisei-jukai). Eventually, Eison and Kakumori parted ways due to differing interpretations of the precepts.
Eison proceeded to rebuild major temples including Saidai-ji, Kairyuo-ji, Hokke-ji, and Hannya-ji, reestablishing strict vinaya observance independently from the Imperial Court.
His disciple Ninshà  expanded the reach of the movement by founding Gokuraku-ji in Kamakura and engaging in active lay outreach. This marked the birth of the Shingon Risshà «, which was initially seen as a reform within Shingon and Ritsu traditions, later recognized as a new school within what is now termed "Kamakura Buddhism".
EisonâÂÂs successors, such as Shinku and Shinsei, earned the trust of the court and helped expand the sect by restoring Kokubun-ji (provincial temples) and converting them into branch temples. At one time, the Ritsu sect (including Shingon Ritsu) rivaled the Zen and Jà Âdo sects in influence. However, Nichiren criticized it as a "Ritsu national pirate" (å¾Âå½è³Â).
Eison and Shinsei also engaged in extensive social welfare work, aiding the poor, the sick, and especially leprosy patients. Tens of thousands were reportedly helped. The defeat of the Mongol invasions of Japan was partly attributed to the protective incantations performed by Eison and Ninshà Â.
The sect declined temporarily during the late Muromachi period, but it was revived in the early Edo period by Meinin. His student Jà Âgen was the first to use the name "Shingon Ritsu-shà «" publicly.
In 1872 (Meiji 5), the Meiji government reorganized Buddhist schools, merging all Ritsu sects into the Shingon sect, citing Shingon Risshà «âÂÂs Shingon lineage. However, independence movements arose within Ritsu temples.
Led by the 64th Elder Saeki Kà Âsà Â, Saidai-ji spearheaded the push for autonomy. In 1895 (Meiji 28), the Ritsu sects regained independence, and Shingon Risshà « was reestablished as a separate sect. Some temples remained within Shingon, however.
Since then, Saidai-ji has served as the head temple of the Shingon Risshà «, and its chief priest customarily serves as the sectâÂÂs chief abbot.