 It placed tanks in the "striking echelon" of the armored division, and placed the infantry in the "support echelon", without directing that tanks should only seek to attack other tanks, thus leaving target selection up to the field commander based on what types of units were available to him to attack.A field manual covering the use of the Sherman (FM 17–33, "The Tank Battalion, Light and Medium" of September 1942) described fighting enemy tanks when necessary as one of the many roles of the Sherman, but devoted only one page of text and four diagrams to tank-versus-tank action, out of 142 pages.This early armored doctrine was heavily influenced by the sweeping early war successes of German blitzkrieg tactics.