What Do You Call the Circular Patch that I Think Warriors Wore?

by SunQuest

A big circle with usually some sort of symbol or pattern there, could be embroidered, could be metal, might have tassels coming off of it. I have no idea what it's called and am trying to find it. I thiiiink it was worn by warriors.

Help me please!

EDIT: Could be Japanese?

EDIT 2: http://imgur.com/r2NyXOP

When_Ducks_Attack

More information needed. Do you have a picture? If not, you're probably never going to get an answer.