I will start by saying I am new at chess.
The scenario is as follows. In a particular game you are in check, but fail to move out of check because you and your opponent did not realize this. Since the rules of chess state that you must not take any move to leave yourself in check or put yourself in check, what do you do? I read that for FIDE fast paced chess they have a stipulation that benefits the "checker"(ie you messed up... sucks to be you). Is this a house rule that everyone abides by? I cannot find anything pertaining to this mistake elsewhere.