Chinese culture has a long history and is broad and profound.
Tips
history
From Bai Juyi's Tang-era epitaph 《海州刺史裴君夫人李氏墓志铭》: 「夫源远者流长，根深者枝茂」 - deep sources make long rivers; deep roots make lush branches. The water metaphor is literal.
usage
Formal praise. Default phrase when describing the length of a tradition, culture, friendship, or institution. Almost always positive.
