Tang poets also wrote ancient-style verse, in which line length and tones were fairly free.
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culture
Since the 2010s 古风 has also named a youth culture: songs with classical-sounding lyrics and Chinese instruments, 汉服 clothing, and art and games set in an idealized ancient China.
history
As a term of poetry, 古风 is another name for 古体诗, the older and freer verse form, as opposed to the strictly regulated 近体诗 of the Tang. The 59 poems of 李白 in this form are known together by this name.