[preommr]

> very obscure branch of mathematics

This is an understatement. He developed a completely different branch of mathematics through papers that spanned hundreds of pages with very dense and very different ideas from mainstream mathematics.

If it was just slightly obscure, maybe all but half a dozen mathematicians in the world might be able to understand his work. As it stands, at it's best, his proof is so opaque that even the brightest (Scholze) can only kind of understand it. At it's worst, they've rightfully identified it as flawed and that even Mochizuki himself doesn't understand that it's wrong.