 However, it was often based on a formal and traditional schema, such as is in a Rime table or rime dictionary, and not necessarily upon actual vernacular speech.The "Pingshui Yun" system was the standard for poetry rhyme from Yuan to Qing Dynasty, even though it was very different from actual contemporary pronunciations.Also, generally level tones only rhymed with level tones, and non-level tones with non-level tones.