píng shēng
level or even tone
first and second tones in modern Mandarin
yā píng shēng yùn
to restrict to even tone (i.e. final rhyming syllable must be classical first or second tone 平聲|平声)
yīn píng shēng
high and level tone, the first tone of putonghua
yáng píng shēng
evenly rising tone, the second tone of putonghua