Patches on the shoulders of army unit uniforms signify the soldier's membership in a particular unit and the unit's type of military service. Army shoulder patches vary in shape, color and design depending on the particular unit.
Army shoulder patches have different significance depending on the location of the patch. For example, if a soldier wears a patch on his left shoulder, it identifies the soldier's membership in a particular unit. If the solder wears a patch on his right shoulder, it signifies that the soldier served in a combat zone while a member of a particular unit. When worn on the right side, a patch is a significant designation of honor.
In 1918, a U.S. Army division first wore unit identifying patches into battle during World War I. Other units soon followed suit, and the shoulder patch designation became a common and important unit identifier in the U.S. Army. Many army division unit patches use the letter A to signify the soldier's membership in the army. Other units, such as the fourth army division, use other designs. The fourth army division uses a white, four-leaf clover set against a red background.
The third U.S. Army division organized in 1918. Its purpose was to advance into Germany and protect critical infrastructure. Third division army members wore a patch with a blue background, white lettering and a red circle around the edge of the patch. The sixth army division uses a red background with a white, six-sided star. The sixth army's color designations of red and white signify that the division is that of a field army.