In the anime Moribito: Guardian of the Spirit (精霊の守り人), when the Star Diviners are speaking and do not wish for the contents of their conversation to be heard, they say something like "There is no-one else in this room." or "This room has only empty vessels." (depending on the translation, I guess). Then, these other guys in the room (generally people who only light candles and the like) pull a piece of cloth that hangs backwards from their 'hat', and cover their faces. This piece of cloth has a symbol, that I guess is a Kanji (I do not know many kanji, so it is only a guess).
What Kanji is this, and what is its meaning?