For every 500 words you write, you gain 1,000 chakra, calling out every week at 5,000 chakra. Here's how the power ranks will work:
0-30,000-E Rank
31-60,000-D Rank
61-90,000-C Rank
91-120,000-B Rank
121-150,000-A Rank
151-180,000-S Rank
Now then, some of you may be thinking "oh hey, 500 words? That's easy, I'll be blowing through these ranks in no time!" Not so fast, as we thought up something for that too..
E-D Rank- 500 words for 1,000 chakra
C Rank- 1,000 words for 1,000 chakra
B Rank- 1,500 words for 1,000 chakra
A Rank- 2,000 words for 1,000 chakra
S Rank- 2,500 words for 1,000 chakra
Though the limit is only 5,000 chakra being gained each week, any extra wc will be put into a rollover, or basically a bank for extra wc that can build up over time so you won't have to worry about not gaining any chakra if you didn't do enough wc one week.
Also please note that if you start out at a specific rank, you start at the BEGINNING of the chakra levels within that rank range.