The advance of the Russian forces upon Erzerum was made from three points. It is well for the reader to keep this constantly in mind. It was an application of the principle of the pincers, combined with a great frontal attack, used so often and so successfully by the Germans in their Russian drive. It adds tremendously to the difficulties of a commander battling to defend a big position. Nowadays, under the new conditions of warfare, fortresses or other positions are not defended to the end. They are held just as long as it is safe for the army within to hold out. But a commander must on no account endanger his force. Discretion is more than ever the better part of valor, and "he who fights and runs away, lives to fight another day," is the guiding principle of the general of modern times. Now this triple menace, striking not only on the front but on both sides and menacing the roads by which a defeated army must retreat, seriously weakens the defense which an army within a fortress can make. It was just such an operation or series of operations that carried the tremendously strong fortress of Antwerp in record time, that accounted for the surprising fall of Namur in two days, and that explains the rapidity with which a score of almost impregnable Russian fortresses in Poland fell before the rush of the German avalanche. The triple Russian thrust at Erzerum was made from Olty, which had been captured as far back as August 3, 1915, along the Kars-Erzerum road by way of Sarikamish, the scene of the great Turkish defeat of the early days of the war, and from Melazghert and Khynysskala. Erzerum was undoubtedly one of the strongest positions in the Turkish Empire, although the experience of the war had tended to detract from previous confidence in the strength of old-style concrete forts when attacked by concentrated big-gun bombardment. Opinions differ on the question of whether or not the Erzerum armament had been maintained up to a modern standard. But as regards the number of its guns, and the size and number of its individual forts, there are no two opinions.