A guitar battle (or guitar duel) is where two or more guitar players take turns soloing, either with or without a rhythm section. The purpose of the guitar battle is to determine who among each of the guitar players present is the most proficient on the instrument. Often, it begins with the guitarists trading licks and phrases, while gradually increasing the complexity of the technique used. A guitar battle can be said to be over when one guitarist outplays (either through skill, endurance, or the other guitarist(s) acknowledging that they cannot win) all the other guitar players present. This is also known among guitarists as a head-cutting duel or simply as cutting heads.