There are so many sects which called themselves Buddhism. My understanding is that only few of them still remain original Buddhism. They are called Theravada Buddhism.
We have many Buddhist sects in Japan, but almost every sects are not from Gotama Siddhatta himself. I was shocked by the fact when I found it as a Japanese. Gotama's Buddhism is rather self-disciplined system. There are no miracle power or mysterious force that saves you. You have to save yourself. You have to do what Buddha said. That's it. I can't do that, anyway. I even don't know I can call it a religion.
Japan's sects are made by these founders, like Kukai, Saicho, Nichiren, Shinran and so on. They are more likely western regions, like Christianity.
I'm still learning it, of course I can't learn everything in my life, so I'd like to know more about it.