Board Thread:Theories and Speculation/@comment-3568954-20150530220024/@comment-734582-20150601103530

GreatestSin wrote: btw, the creator himself labelled it as kinjutsu since it was to chakra-consuming i doubt that a genius of his lvl would overlook something that convenient in his own creation :) No, that's wrong. It's a kinjutsu because it evenly divides the chakra among clones (See: Naruto vs Neji). Because of this, a huge amount of chakra is needed to make any use of it. Kakashi never used it because Raikiri is a jutsu that takes up significant fractions of his chakra. Kakashi also mentioned that if a Jutsu is forced when Chakra is too low, the user can die. See: Sasuke learns Chidori, Kakashi uses Kamui on rocket in Pain's invasion.

The dangerous combination that results is that a user can make enough clones to drop below the chakra threshold, force his training jutsu and die from lack of chakra without a drop of it consumed.

Kakashi used i think one or two Clones. Judging from the power of Raikiri he actually has chakra levels approaching (or matching) a kage. The First and Second hokage could only make a dozen or so while maintaining a barrier. Madara could make 25 clones that each matched the strength of a kage. Kage Bunshin no Jutsu is thus apparently a jutsu normally only used by Jonin and above, and by ones with plenty of chakra.

I would like to point out that it's doubtful that Naruto accumulates chakra training from this. After all, Kage Bunshin is a chakra "reserve" split off. Returning it returns it's reserve, then the deficiency is inflicted on the user. This "deficiency" can also be an excess of chakra (see: naruto uses clones to accumulate natural chakra). It makes sense that if the clones use chakra, they "pay" it out of their own pool. Upon being undone, the leftover chakra is returned to the user. In Naruto's case, he felt nothing until the Jutsu was broken. Which makes sense, because the payment is not done until the jutsu is broken. Only upon breaking does naturo feel the "payment" of all the techniques in his body since it previously was maintained in each "reserve". And so, in stead of using a technique over and over, his body experiences the payment as one giant jutsu used in one go. Which is probably why he instantly collapses.

From this (payment) perspective, naruto does train his reserves of chakra. However, it's equivalent to just spamming the used jutsu over and over, and so no additional gain is made from Bunshin other than depleting your chakra faster.

The source of Chakra seems to be in the cells, and so a cell-less being like a clone has no use training this.

Finally: Muu was able to physically split himself, at the cost of halving all his attributes (Rather than just halving chakra). So while each clone can train, they can only train half as well. Thus, it's the same as training yourself twice as hard. AKA no gain is made.