Street football, also known as backyard football or sandlot football, is an amateur variant of American football primarily played informally by youth. It features far less equipment and fewer rules than its counterparts and, unlike the similar touch football, features full tackling. Main rules An organized version has seven players to a side, such as in the American 7's Football league (A7FL); however, such organization is rare, players per side can range from as few as one ("one on one" football) playing both sides of the ball to dozens. Games are played on fields generally ranging from as short as 10 to as large as 50 yards, with the occasional game being played on a full-size regulation 100 yard field such as in the A7FL. Generally, the larger the field, the more players that can be incorporated into the game. The A7FL plays on a full-size regulation field in regards to length, however, the width of the field is shortened, from approximately 50 yards, to 40 yards in order to accommodate fewer players on the field. Teams are typically assembled from scratch. Most forms of backyard or street football use ad hoc house rules that vary from neighborhood to neighborhood. The two teams organize on opposite sides of the field for the kickoff. Because of skill, field size and other issues, this is usually not a kickoff but rather a punt-off or a throw-off. Many versions skip this process and start the offense at a certain point, similar to a touchback in other national leagues. As in regular American football, each team usually has four downs per series. In order to achieve a series of downs, backyard football requires the team with the ball to complete two passes or reach a certain point on the field. Few games include enough people, or the proper equipment, to run a chain crew to maintain the 10 yard familiar in most organized leagues. These structures encourages passing plays over running, as does the usual lack of offensive and defensive lines. The use of a center is optional, depending on the rules set forth, and other ways to start the play (e.g. the quarterback picking up the ball directly, or holding the ball out prior to starting play, then pulling it back to begin) are often used in lieu of a snap. Play continues until there is a turnover on downs (i.e. the offensive