What was the testing based on merit and effort in han china that determined who would get government jobs?

In ancient China, the government was run by the civil service. The were people who reported in to the emperor. The top civil servants were usually ministers, who were very wealthy and powerful government officials.In order to become a civil servant, one had to pass a test, the Chinese Civil Service exam. The better they did on the test, the higher position they could get in the civil service. The tests were very difficult. There were 9 different levels or ranks of civil service. People could move to a higher rank by passing the next level.