The Yayoi times in Japanese history was when the building of tombs was in prominence and thereby the Yamato clan gained importance. The Jomon times leave no clue about Japanse songs. The Yamatos established law and used language that resulted in making the imperial court which remained in the Heian and Nara period. The court automatically resulted in Japanese court music which was also present in Kojiki and Nihon Shoki. The rule of Emperor Temmu encouraged making these songs into compilation.
There is also more variety with respect to the Chinese and Japanese languages wherein the Chinese is mostly monosyllabic with tones whereas the Japanese does not have tones and exists in long sentences. Again the Heian and Nara times in history were highly influenced with Buddhist culture and chanting is a very important facet of Buddhism. The Shomyo began gaining importance as in bifurcation existed as Shingon and Tendai Shomyo. The Joruri was also traced from Noh and Heike Biwa with a definite resemblance with Shomyo.
Uta means a poem or a song.
Poems often are told in high loud sounds and poetic history of Japan is remarkable. Manyoshu nad Kokinshu are typical during the Heian and Nara times. Prose and poems existed with the dialogues in dramas at the performances in the imperial court. The lute and flute were the chief components in instrumental music and The Gagaku dances are famous till date.
Shomyo or Buddhist music is an amalgamation of recitation of three languages like the Sanskrit with its origins from India called Bonsan.
The Chinse chanting happen in Kansan and the Wasan is Japanese.
The Shingon and Tnedai Shomyo are the main two brances.
Imayo on the other hand refers to modern trend and has short items of Wasan Shomyo. This is usually in four lines which was made popular by the Shirabyoshi dancers. Imayo was usually popular with the upper class during the Heian times. Etenraku is a form of Gagaku which is noticed in the folk music of Japan.
Modern forms of Japanese music are westernized with the merits of pop culture. There are melodious Japanese songs for children and the Japanese opera songs are a treat to the music lover. However heavy the borrowings from other cultures may be there is something very typical about Japanase music and songs have the traditional touch present in each performance.