It was Kakinomoto no Hitomaro, he has written 137 poems about Tanabata.
Man'yōshū is the oldest existing collection of Japanese poetry, compiled some time after 759 AD during the Nara period.
Kakinomoto no Hitomaro was the most prominent of the poets included in the Man'yōshū. He was particularly represented in volumes 1 and 2.
Hitomaro is famous for his long poems, such as "In the sea of ivy clothed Iwami", "The Bay of Tsunu", and "I loved her like the leaves." 19 of his chōka (or nagauta, "long poems") were comprised in the Man'yōshū and 75 or so tanka (or mijikauta, "short poems") were likewise selected. Many of his poems were written on the topics of public occasions, such as his "Lament for Prince Takechi", written as part of the mourning ceremonies for Takechi.
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