Futsal is a football game played on a hard court, smaller than a football pitch, and mainly indoors. It has similarities to five-a-side football. Futsal is played between two teams of five players each, one of whom is the goalkeeper. Unlimited substitutions are permitted. Unlike some other forms of indoor soccer, the game is played on a hard court surface marked by lines; walls or boards are not used. Futsal is played with a smaller, harder, low-bounce ball than soccer. The surface, ball and rules together favour ball control and passing in small spaces. The game's "emphasis is on improvisation, creativity and technique".