Best way to do redirection?

Hi, i have a site that is up few yeas now, and i wanna change urls.
site.net/category/”name of he category”
That is our url struction for categories, and we now wanna change that. We can change but then will lose visitors that come to old structure urls.
So, what is the best way to do redirection automaticly
from any url that comes with /category, that now goes to /kategorija?
Thanks in advance.