"push or knock". This literary allusion
means "to try two alternate wordings" in a composition.
It originates in the story of the Tang dynasty poet Jia Dao who was composing a couplet while riding on a donkey to the capital:
"Bird roosts in pond's-edge pool,
monk pushes on below-moon door."
Then he tried it with "knocks" in place of "pushes", but he couldn't decide which was better and started making pushing and knocking motions with his hand to try to visualize which was more vivid
He rode some distance like this, moving his hand and mumbling the alternate lines to himself. Eventually, without realizing it, he rode right into the city and up to the poet Han Yu, who held an important office at that time. Attendants stopped the donkey, and Han Yu stood there for some time, waiting for Jia Dao to finish. Finally Han Yu said, "It sounds better with 'knocks'."
"Push or knock", a vivid literary allusion, has become the standard way to say "to fuss over wording" in Chinese. A stronger and more disapproving way to say this is yao3-wen2 jiao2-zi4 "to chew on the words".
Other Chinese literary allusions