Chunin

Chunin (literally "Middle Ninja", Viz "Chūnin" and "Journeyman Ninja") are ninja who are qualified to watch over and guide other ninja. Chunin have reached a level of maturity that primarily consists of leadership skills and tactical prowess. Some of them, like Shikamaru Nara, serve as team leaders in charge of small teams who need to make decisions and utilize the skills of the shinobi under their command to the maximum effect. Upon reaching Chunin level, ninja can wear an identifying tactical vest that holds ninjutsu scrolls. This vest is not required; instead, some look for more elaborate clothing like capes or robes. Chunin are typically sent on C or B-rank missions.
To become a Chunin, a Genin participates, with his or her team, in a large examination, known as the "Chunin Exams," hosted twice a year due to the growing number of ninjas. In the past, each village held their own Chunin exam. After the 3rd Ninja World War, allied ninja villages agreed to hold the exams together at the selected village that would host the exam, so villages could improve and strengthen their relationships. Another advantage is that ninja that took the exam might attract clients who are interested in hiring them. The exam is a test not only of strength, but information gathering abilities, survival skills, and adhering to guidelines. Those who have all of these qualities are grouped together into predetermined fights, watched by a council that decides who becomes a Chunin and who does not. While the winners are able to proceed to fight the next opponent, it is aptitude, rather than winning, that is evaluated to determine whether a candidate is promoted. This way even one who loses his or her first match can become a Chunin as evidenced by Shikamaru's promotion while he surrendered to Temari in the first round.