Qing vs Warring States

Qing

name
  • Qing dynasty (1644–1912), the last imperial dynasty of China. 

Warring States

name
  • The era in ancient Chinese history following the Spring and Autumn period and concluding with the first imperial unification of China under the Qin dynasty (c. 475 BC to 221 BC). 

  • The era in ancient Japanese history of social upheaval and military conflict known as the Sengoku period that came to an end under the unification of the Tokugawa shogunate (c. 1467 – c. 1603). 

How often have the words Qing and Warring States occurred in a corpus of books? (source: Google Ngram Viewer )