"Waka" - Japanese poetry. "Wa" means Yamato," ka" means poetry. and the word became widespread mainly after the Heian period, based on the idea of Japanese poetry as opposed to Chinese poetry. In the oldest collection of Japanese poems, the Manyoshu, the writing of "waka" is limited to examples that mean "a kotafuru uta (a poem that makes you sigh)". "Waka" is a form of poetry that is generally 31(5-7-5-7-7) characters long, and this fixed form of poetry was the mainstream of Japanese poetry for a long time. Waka poems are basically written in Japanese, avoiding the use of Chinese words, and the use of slang is also restricted, so there was a certain sense of norms in the terminology used in poem.