The grand tactics of chess, an exposition of the laws and principles of chess strategetics, the practcal application of these laws and principles to the movement of forces; mobilization, development, manoeuvre, and operation (1898)
Young, Franklin Knowles, 1857- · Boston, Roberts brothers · leaf 139
110 THE GRAND TACTICS OF CHESS. Echelon. — The Echelon is a supplementary formation in which either the K B P and the K Kt P, or the Q B P and the Q Kt P, are posted at their fourth squares, for the purpose of supporting and sustaining the major right oblique or the major left oblique,… … (White.)
Chess
Internet Archive · University of California Libraries · Public domain (published before 1931). Free to use for anything.