Board Thread:General Discussion/@comment-24031741-20140104200613/@comment-5398287-20140104220033

That's not why he's classified as a master. In episode 248, he used Raikoho - a very powerful and high-level spell - without any incantation, and his resealing of the Jokaisho proves he knows quite a bit about Kido. Besides, instantaneously using a low-level spell to full effect without incantation is still considerable.

And before you claim that doesn't matter because it only happened in the anime, Yoruichi has only used Kido spells in the anime, which is why she even has a Kido sections in her Powers & Abilities section.