While United States Army uniform regulations explicitly authorize the wear of shoulder cords by members of the Infantry (Infantry blue cords) and specialized marksmanship units (blue with sequential red, white, and blue markings), Commanders are authorized to mandate the wear of branch-colored shoulder cords as a way to commemorate special occasions or as part of a special ceremony. In such instances, black shoulder cords would be worn by members of the Chaplain Corps; its only enlisted Military Occupational Specialty 56M, Religious Affairs Specialist.
But shoulder cords are often worn as part of ceremonial uniforms or as a distinctive accouterment to recognize a special achievement in a several military-related organizations, as well as by member of civilian organizations such as fire or police departments. Some examples of groups that authorize the wear of black shoulder cords include (but are not limited to) the U.S. Army Junior Reserve Officer Training Corps, where it is issued to cadets involved in adventure-type activities, and in the U.S. Naval Sea Cadet Corps, it is worn by cadets who are Color Guard Commanders or members of the Color Guard and Honor Guard.