1911 Encyclopædia Britannica, Volume 6… (1911)
“ Diagram 2.—Showing English and German Methods of Notation. “Check and Checkmate.” The king can never be captured, but when any piece or pawn attacks him, he is said to be “in check,” and the fact of his being so attacked should be announced by the adverse player saying “check,” whereupon the king must move from the square he occupies, or be screened from check by the interposition of one of his own men, or the attacking piece must be captured. ”
