Branch names with slashes

Hi

Branch names can contain slashes, so we can use 'development/foo' as a
branch name. If I choose 'development' as a branch name, it doesn't
work. There is a directory named development at '.git/refs/heads'
directory. So we cannot create a file named development for
'refs/heads/development'.

An error message may occurs like below. Unfortunately, It is not of help to me.
'error: 'refs/heads/development/foo' exists; cannot create
'refs/heads/development'.

I think that dealing with a file system and an error message above is
not sufficient for a novice like me. I hope that it should be
improved.

Thanks for your response.
Leonardo YongUk KIM