idiom > trace to the very source of sth.
Contents
穷源溯流
Pinyin: qióng yuán sù liú

Explanation: 源:河流发源的地方;溯:逆流而上。原指逆流而上探寻河流的源头。现比喻探究和追溯事物的原由。

Source: 清·王十禛《然灯记闻》:“为诗要穷源溯流,先辨诸家之派。”

qióng yuán sù liú
  Pursuit of the root causes of things and explore their development through
Translated by Google
English Expression
  1. n.:  trace to the very source of sth.