唐宋词格律

Rising in Tang dynasty and prospering in Song Dynasty after Five Dynasty, poem is a kind of Yuefu poem which can be sang with music. Because of close relation bewteen the words and music, it produces the strict rhythm and the characteristics of form.Every poetry is destined to have its regular principle: poetry definde by sentenses , sentences defined by words and words have definate sound, as usural, most poetrys have irregular length with different ryhme in order to adapt themseleves to the merers of music.