Board Thread:Wiki Discussions and Support/@comment-1207741-20150425210552/@comment-3279282-20150426093036

暗部 is a normal, shortened version of 暗殺戦術特殊部隊. It's not an acronym like NATO, where every letter stands for a word, but like Interpol and thus should be written as "Anbu".

The opinion on the community on these things doesn't matter. They don't change grammar rules. Even if all of you were against writing it "Anbu", ANBU wouldn't be more correct.