A-rank is one of the six shinobi classifications for level, techniques, and missions. It is preceded by B-rank and followed by S-rank. It typically refers to techniques used for Kages or Jonin. A-rank techniques are very powerful, but need extensive and long training to be fully mastered. Some A-rank techniques may also pose a threat to the user itself, leading it to be classified as a forbidden techniques.
A-rank missions refer to an assignment related to the hidden village or it's home nation's personal interests. They are extremely difficult and may be even suicidal, and as such they are assigned to a Jonin. A-rank missions pay between 150,000 and 1,000,000 ryo.