The Pure Magic of Taika

The pure, raw form of magic. There isn't much it can't do. Anything the other schools can do, you can do with this as well.
To learn the Pure Magic, one must learn several things. It isn't as simple as using a different set of runes while building the spell circle. While it does use spell circles, unlike other schools it uses several sub-circles, where it breaks down into at least six circles. It uses a completely different language to all other schools as well, so you'd need to learn that language before you can learn to use the Pure Magic. One big issue for anyone seeking to learn it is the lack of internal logic. There aren't any rules about how the language works.
Secondly, it's very hard to perform the incantations themselves. This is because of how the language is built and the pronunciations.
Thirdly, it's a far more exhausting compared to normal magic. Handling this will be draining as the body will need to handle it in its raw form, but you do avoid the corrupting effects of changing the nature of the arcane energies itself.
Finally, the circles are harder to draw, not just because they consist of multiple circles, but also because the writing will cross over each other. So the runes will be drawn on each other. This introduces the risk of messing up the runes you've already written.
The Pure Magic takes even longer to use, but with its unlimited possibility, there are many mages who'd gladly accept it.