Definition– a directed effort to obtain detailed information of a specified route and all terrain from which the enemy could influence movement along that route.

The recon/vanguard moves ahead of the main body in an effort to detect obstacles and threats. In the below picture the black line/arrow is the direction of travel of the main body. The dotted butterfly patterns are the recon/vanguard teams. They move ahead checking both sides and forward. They would report back before the main body would advance. The second picture is a more elaborate route recon with 3 teams moving out and checking both sides of the road.  The goal is to ensure the route is safe for the main body to advance. Thoroughness and speed need to be balanced based on mission objectives.