In my experience, through testing with friends, different characters and even Kakashi in a range of situations.
I've never been able to to observe a noticeable difference in damage or effects of any kind with the Nin/Atk *ion stats, the runes still add power but they don't actually seem to affect damage.

Those stats are particularly hard to level up too and we had Red Runes boosting them by over 50% which should be quite significant in some way, but yet no observable difference in damage/fights, so for the time being they seem practically irrelevant.

You can never go wrong with Core Stats + Initiative though, even if they did work, I don't believe Injury works either but I don't remember testing it.

if im not wrong (just quoting what iv read earlier) these dont work at all / "that well" or not the way we are expecting them to work.

Iv heard the dmg reduction one reduces dmg done when one of your ninjas is under chaos (blah if thats true) never botherd testing that out myself. but i havent testet out the atk/nin pen myself but just guessing on how "little" power they give compared to the others, they shouldnt be prioritized over HP/Att/Def/Nin/Crit/Combo/Inj/Init. They do give a powerboost, so it does have some effect we just (or i) dont know that yet. Had a red one of one of the pen one and it gave nice boost but i didnt see any "big" difference tbh.

what is maximum level for those chakra ?

11

Hi! Sorry for the late response. I personally only knew a small fraction of the information about Taijutsu/Ninjutsu Pen and asked for a better clarification. It is a difficult concept to grasp but I will try my best to explain what they do.

Pen. does not affect normal damage, it affects Critical. What that means is that the more Pen you have, the more damage that type of critical will do. Taijutsu Pen corresponds with Defense, while Ninjutsu Pen corresponds with Resistance. Due to Defense and Resistance, there is a cap to the amount of damage a Critical can do. By increasing the amount of Pen you have, you increase the cap to the amount of damage you can do, which effectively increases your damage.

TLDR: More Pen = More Critical Burst

Note: This information is courtesy of Tobei, hope it helps!

~Jib

So if you always hit criticals it would be worth using *ion stats then.. Thanks. :) Thats good to know. (I hit critical about 60% of the time in pvp versus my own server *I have better refines then all but 2 players in my server.