The Man'yôshû, literally, "Collection of Ten Thousand Leaves," is an anthology of 4,516 Japanese poems compiled in or just after AD 759. Traditionally said to have been compiled by a poet named Ōtomo no Yakamochi, the collection's importance in the development of Japanese language and culture is difficult to overstate.
Not only does the Manyoshu constitute the earliest known Japanese poems in existence (with the possible exception of some folk songs in the Kojiki), but it also was the first concerted attempt to use Chinese characters to phonetically represent the native Japanese language. The writing system of the Manyoshu, now known as "manyogana," would eventually evolve into both the katakana and hiragana scripts still in use in Modern Japanese.
Moreover, the ideas, phrasings, and concepts embodied by the Manyoshu poems have had a deep and enduring impact on Japanese literature and culture in general that defies easy comparison. Perhaps Shakespeare's impact on the English language bears some resemblance. Every day Japanese people, usually unknowingly, quote proverbs, use expressions, or employ idioms that trace their origins to a line in the Manyoshu.
The majority of the poems in the collection follow one of two related forms, the choka, or "long poem," consisting of alternate lines of five and seven syllables, followed by a final line of seven syllables, and the tanka, or "short poem," consisting of 31 syllables in five lines of five, seven, five, seven, and seven syllables. Many of the poems were composed decades or even centuries before they were collected, and generally are informed by timeless themes of love, life, and loss.
One of the major contributors to the collection was Kakinomoto no Hitomaro, whose 474 contributions have made him one of the most famous of Japanese poets, despite the fact that almost nothing is known about his life.