Yes. By a man named Hagoromo Otsutsuki, a distant ancestor of mine.

（ he does not know the whole sad story, but he knows enough. ）

Chakra, as with your qi, can only be molded by those with the potential to externalize it. We do not have cores, as you speak of, but we do have eight 'gates' in which chakra is stored throughout our bodies. Similarly, such chakra can be used to heal or fight as necessary to the individual.