An indoor percussion ensemble or indoor drumline is a type of marching ensemble consisting of battery and front ensemble instruments. It differs itself from a traditional percussion ensemble by not only on musical performance, but on theatrics and marching. Although most indoor percussion ensembles are affiliated with high schools (also known as scholastic groups), there are also many independent groups that draw participants from a large area and are independently funded. Independent groups typically start rehearsing in October, while high school groups typically start after their fall marching band season ends. Because of this, the activity is often called winter percussion or winterline. History The athletic arts were looking for a new intriguing sport that could challenge and excite skilled musicians, so they started creating their own styles all over the world. Since then, marching percussion has advanced and moved into auditoriums and gymnasiums as percussion ensembles looked for ways to maintain their skills during the winter months when performing outdoors on football fields was not practical. Following in the footsteps of indoor guard ensembles, indoor percussion ensembles arrange music and motion appropriate for a more intimate setting. The activity is enjoyed throughout the United States and Japan, as Winter Guard International (WGI) provides many regional and national opportunities to compete. Percussion ensembles first appeared in WGI shows in 1992, and the theatrics, sets, and music selection has advanced throughout the activity's history. There are many organizations unaffiliated with WGI that hold smaller regional shows all over the world. As the number of ensembles that competed in WGI competitions grew, different skill level divisions ranging from A class to World class. Competitive groups are held to specific times and judged on criteria that change every season as technology and creativity blossom. These ensembles compete, but traditionally, the musical sport is treated as a place to grow together as a community, learn new techniques, and enjoy the work done by peers from across the country and locally. Competition became international when Color Guard Netherlands (CGN) introduced indoor percussion in Europe. In 2008 CGN hosted the first WGI Regional for percussion outside of North America. Since then, WGI has expanded even further to parts of Asia and Africa. Music Music is arranged based on original works as well as recreations of movie themes, popular music, classical music, and more. Instrumentation is anything that would or could be used under the percussion category