Tanka (短歌) is a form of Japanese poetry, an even older form than
haiku. It consists of five lines with a pattern of syllables in each line as follows: 5-7-5-7-7. To be exactly, it is contained in
waka[?], which consist of tanka, choka, etc. But usually, waka is equall to tanka. Each line contains a separate image but a unifying image runs through the entire poem.