Board Thread:Naruto Discussions/@comment-24847491-20140921145042/@comment-1512913-20140924104942

But Yang isn't life force. Even databook distinguishes between chakra and life force. Chakra is half made of physical energy, so if physical energy were life force, chakra would be life force, but it isn't.

Naruto could barely keep Obito alive with Yang chakra, life force on the other hand can not only bring dead back to life but even give life to inanimate objects as shown with Chiyo's attempt with the puppets and Kabuto animating stalactites in the cave.