Zhongyuan Yinyun

The author of Sanqu, Zhou Deqing, delved into the research on Beiqu, discovering that it created many problems by not adhering to the rules of classical poetic composition.

According to his own experience, he was able to propose a set of rules for composing and reciting Běiqǔ, which came to be known as Zhongyuan Yinyun.

The traditional ru sheng (入聲 "entering tone") is assigned to three groups according to contemporary rules in some modern Ji-Lu Mandarin dialects.

Zhou regarded the principal works of the Four Great Yuan Playwrights (元曲四大家; Yuanqu si dajia) as foundational to verse in general; he considered their works to be "rimes joined with nature, words able to connect with the language of the world" (韻共守自然之音，字能通天下之語), and at the same time also distinguished where the playwrights used rimes in non-standard places.

The second half of the Zhongyuan Yinyun, Zhèngyǔ Zuòcí Qǐlì (正語作詞起例), employs various examples to explain in detail both the rime charts' methods of use as well as issues concerning Beiqu's creation, standards and other aspects.