Manual for Noncommissioned Officers and Privates of Infantry of the Army of the United States, 1917 / To be used by Engineer companies (dismounted) and Coast Artillery companies for Infantry instruction and training

by United States. War Department

Section 6. Flank guards.

A flank guard is a detachment detailed to cover the flank of a column marching past, or across the front of, an enemy. It may be placed in position to protect the passage, or it may be so marched as to cover the passage. The object of the flank guard is to hold the enemy in check long enough to enable the main body to pass, or, like the advance guard, to enable the main body to deploy. Like all other detachments, it should be no larger than is necessary, and should not be detailed except when its protection is required.

When a flank guard consists of a regiment or less, its distance from the main body should not exceed a mile and a half. Practicable communication must exist between it and the main body. The flank guard is marched as a separate command; that is, with advance or rear guards, or both, as circumstances demand, and with patrolling on the exposed flank.