Re: Secret behind Obito's Kamui?
No, the Sage of course used BS, but a part of the BS he used to create, was called Izanagi. And that same part, the Uchiha's will later use in their kinjutsu, but it was different from the Sage's use of Izanagi, who had the rinnegan and the perfect body when using it.
Izanagi was part of BS, according to the manga says. Its one side of BS, its not seperate from it.