Jōnin

are generally highly-experienced ninja with great individual skill who serve as military captains. They are often sent on A-Rank missions, and experienced Jonin may even be sent on S-Class missions (which are considered to be the greatest difficulty). It is not unusual for Jonin to go on missions alone. Jonin are generally able to use at least two types of elemental chakra, some genjutsu, and above-average taijutsu skills.

It is as of yet unknown what one has to undergo to become one. It is mentioned in the Naruto Anime Profiles databook that Jonin are appointed, however there was mention of a Jonin exam in the anime's Kurama filler arc. When a ninja becomes a Jonin, he/she may be assigned three Genin to look over. One part of their duties is to help instruct and train these Genin to become competent ninja.