Single Comment

In casual games and in rapid chess one normally just continues playing, moving the king out of check. If both players agree, however, they can go back to the earlier position. In tournament games, if only a few moves have been made, one would typically go back to the checked position and continue from there. As moves are recorded it's easier. However, if one player has achieved a winning advantage many moves later, one cannot go back, but must play on.
/Mats