No Last-Minute Maneuvers
Experience has shown that last-minute maneuvers were likely to create dangerous gaps in the lines, or to expose a marching flank to missile or shock attack. Therefore tactical ingenuity was not often attempted beyond the point where an enemy would be forced to enter battle on unfavorable ground, or with only a portion of his available forces. The usual objective in battle was to outflank the enemy, since only the flanks and rear of well-armed infantry—10 to 30 ranks deep—were sensitive and vulnerable. Though we shall note a few examples of successful deviation from the parallel order of battle, such deviations more often led to failure.
— The Encyclopedia of Military History, p. 17