A B-rank ninja has 350 chakra. The requirements to rank up from B-rank to A-rank are as follows -

B-rank or higher in at least 3 stats. yes, B-3 in perception and dexterity, B-2 in speed.

At least 4 A-rank or higher jutsu trained, in addition to free jutsu.
1) Sixteen Pillar Bind
2) Plasma Barrier
3) Otter's Breath
4) Guanyin Otter Nuzzle

Complete 6 threads consisting of any combination of A-rank missions or non-mission threads containing at least one other PC which reach a minimum of 3500 words and 2 posts per person.
1) http://www.narutosaga.com/t30373-invite-blood-under-the-sunset#239248
2) http://www.narutosaga.com/t30442-blueshift-dreams-ii
3) http://www.narutosaga.com/t30468-yoga-at-sunset
4) http://www.narutosaga.com/t30378-a-girls-night-out-chiaki
5) http://www.narutosaga.com/t30444-rivers-of-time-rivers-of-emotion-myrddin-private
6) http://www.narutosaga.com/t30470-i-don-t-care-i-love-it-chiaki (in progress)