Originally Posted by
scotbud123
^Yeah, they explained that during the Pain arc. You make normal chakra by combining Spiritual Energy and Physical Energy. (Which was explained during original Naruto, like episode 40 or so when he trains with Ebisu and Jiraiya). "Sage" chakra is made by adding in Natural chakra from the atmosphere/air and terrain/ground.
Basically what you said, while Ninjutsu is made with ONLY Yin and Yang, Senjutsu is made with Natural chakra added to the mix. :P Hence Obito can't counter it.
Pics for reference:
[img]https://images.wiki*****m/naruto/images/2/28/Chakra_Moulding_Diagram_%28Normal%29.svg[/img]
[img]https://images.wiki*****m/naruto/images/1/12/Chakra_Moulding_Diagram_%28Senjutsu%29.svg[/img]