An instrumental genre with fast tempo, chaharmezrab shows a player's technical dexterity when performing fix-metered pieces. It is characterized by a fundamental motif repeatedly manifesting itself interrupted by melodic figures of music. Chaharmezrab is composed both for a solo instrument and for and ensemble . It is quite possible that while improvising, the player also improvises a chaharmezrab. There are examples of chaharmezrab in radif. Famous examples contain Chaharmezrab-e Mahur, by Darvish Khan.
Source: An Introduction to Iraninan music booklet from Mahoor Institute of Culture and Art