The Thousand Character Poem (千字文) is long in Han script (漢文の長詩), all in 1000 different characters, which was commissioned by Emperor Wu of Liang of the Southern Dynasty (南朝梁時代の武帝) to the writer Zhou Xingzhi (周興嗣).
In 250 verses of four words each, the subtle emotional movements of human life are beautifully sung in rhyme. For example, here are the first four letters and their meanings.
天地玄黄 means that the sky is high and black and the earth is low and yellow. The darkness of heaven and earth is so dim with infinite expanse.
The Thousand Character Poem is in two different styles (kaisho and gyosh. Subsequently, several other thousand-character styles were created, such as the cursive thousand-character style and the standard thousand-character style. There is also the 'Four-Tai Thousand-Character Sentences'(四体千字文), in which thousand-character sentences are written and arranged in tensho(篆書), (隷書), kaisho(楷書) and sousho(草書).
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Source: (1) Thousand-character sentence - Wikipedia. https://ja.wikipedia.org/wiki/%E5%8D%83%E5%AD%97%E6%96%87.(2) What is Senjimon (千字文)? Meaning and usage - Cotobank. https://kotobank.jp/word/%E5%8D%83%E5%AD%97%E6%96%87-88326.(3) Senjimon, by Kitamukai Unchiku - Familiarisation with the classics | National Institute of Japanese Literature. https://www.nijl.ac.jp/koten/kokubun1000/1000kato-sino.html.(4)30-2_06LEE.pdf (ritsumei.ac.jp)(5)Santaisennjimon:Gado Ono ISBN978-4-8373-0452(6)Senjimon: Kanju Ogawa ISBN4-00-332201-0