The manji (swastika thing) is the "ban" in "Bankai" Heero's right, it's also used in Buddhism for the ideas of "rebirth" and reincarnation.

But that does bring up the issue of censorship. What will happen when they try and show this on American TV when Bleach is eventually licensed? Surely a lot of people will take it the wrong way and assume it's just Nazi propaganda or some such BS.