Eika (go-eika) are verses or gathas of praise composed in a 31 syllable (tanka) form of 5-7-5-7-7. These gathas originally were written in Chinese characters from Chinese compositions, but were popularized in Japanese script among the common people of Japan as Buddhist gathas of praise composed in a 7-5 rhythm. Although eika are known in this traditional 31 syllable form, they are also known from the gathas of praise that people composed on prayer votives when pilgrimaging to temples. These latter eika began with the pilgrim gathas of the 33 Sites of Shikoku Island, where each site contains one eika. It has been discerned that the writer of these was Emperor Kazan (968-1008). Following the 33 Sites of Shikoku, various pilgrimage sites such as the 33 Sites of Bando, the 34 Sites of Chichibu and the 88 Sites of Shikoku became popular, each one having their own eika. There have also been eika created that are not associated with pilgrimage sites, such as the eika of Zenko-ji temple, and the eika of Bodhisattvas Jizo, Kannon and Yakushi. These show longer forms of eika in a call and response style. In popular belief, eika are not restricted to pilgrimages but also have been composed for Nembutsu Associations (nembutsu-ko) and Funeral Associations (mujo-ko). Eika from individual grave sites have also been found and traced back to the end of the Heian Period (794-1192). In the Kamakura Era (1192-1333), eika were used as one method of propagating teachings and this had a great influence on their subsequent development. Gathas of the Buddha's teachings and gathas of praise influenced the establishment of individual temples in the middle ages, and it is thought that practice of one eika for every grave site comes from the beginning of the Edo era (1600-1868).
Eika were subsequently developed in to hymns (eisho), such as the old ones of the Yamato School. In the early modern era, each Buddhist sect created their own fully developed hymnal styles such as Shingon shu's Kongo lineage and Zen shu's Baika lineage. From 1946, Jodo Shu propagation activities focused on the development of hymns from these gathas. The melody is different from traditional, arrhythmic Japanese music of the masses. A new kind of melody using major or minor chords was constructed which includes the use of the western musical scale. In the modern style, there are two types: one has an eight beat melody composed of two verses of opening and development; the other has a sixteen beat melody composed of four verses of change and conclusion.
The gathas for these hymns come principally from the tanka created by Honen. There are the very old gathas which feature classical lyrics in a 7-5 rhythm, such as the Guiding Light (raiko) Gatha, the Kurodani Gatha, and the Japanese ABCs (iroha) Gatha. There are also new gathas with new lyrics in the 7-5 rhythm, such as the Honen Memorial Day (gyoki) Gatha, the Buddha's Birthday (hanamatsuri) Gatha, the Spirits of the War Dead Gatha, the Dead Spirits Festival Gatha, the Ten Night (juya) Gatha, and the 800th Anniversary (kaihachi) Gatha. Although these have a slight hint of the western musical scale, they use new melodies created from popular folk music styles. In general, the music of popular Buddhism has been greatly influenced by regional folk songs.
Further, both traditional Japanese instruments, like bell (rei) and gong (sho) percussives, and western instruments, like piano, organ, flutes and strings, have been incorporated. Other sects have their own peculiar styles and arrangements concerning instruments. Finally, dance has also been added to accompany these gathas and hymns. In such a way, these hymns have become like "assisting acts" (jogo) of the nembutsu with fervent recitation and dance. Again, other sects have very different styles to their hymns which are popularizedthrough local temples.
The Jodo Shu Chanting Committee (eisho shingi-kai) presides over the organization and development of chanting, hymns, and the Yoshimizu Choir. In Jodo Shu, there are four principle ranks of chanting with their own sub-levels. The highest is Eisho-shi (5 levels), then Ei-san-shi (3 levels), Eisho-kyoshi (5 levels), and Eisho-kyodoshi. As well as the main Yoshimizu Choir of Head Temple Chion-in in Kyoto, there are the particular ones of the seven Main Temples and of each of the regional districts of Jodo Shu. These choirs number up to 520 with 8,000 participants stretching through most of Japan from Aomori in the North to Kumamoto in the South.