A player is said to have the opposition when he can place his King directly in front of the adverse King, with only one square between them. This is often an important advantage in ending games.
Howard Staunton (1876). “The American Chess-player's Handbook: Teaching the Rudiments of the Game, and Giving an Analysis of All the Recognised Openings : Exemplified by Appropriate Games Actually Played by Morphy, Harrwitz, Anderssen, Staunton, Paulsen, Montgomery, Meek and Others : from the Work of Staunton”, p.22
