Form of instrumental pieces employed in Ottoman music
Pesrev: Generally composed in major rhythmic patterns, such as "Darb-i Fetih", "Sakil", "Muhammes" and "Devr-i Kebir", or sometimes in minor ones, such as "Duyek". It is a saz work that emerged from the sections called "Hane" and the "Mulazime" section that comes between and is repeated with little change.
Saz Semaisi: Although they have the same structure as the peþrev, the saz compositions falling in the semai (six-time), "aksak semai" (10-time) and yuruk semai (six-time) categories are known as "Saz Semaisi". These come at the end of the fasýl, following the yuruk semai.
Taksim: Intended to introduce, prepare the way or warm up for the makam, these are played with a single instrument, within the makam, yet not linked to any rhythmic pattern, and are either free-form or improvised.
Oyun Havasý: Instrumental pieces composed for dancing.
Usul: Up to 15-time these are known as ‘Küçük Usul’ (minor pattern), and after 15-time as ‘Büyük Usul’ (major pattern). When the two are employed together, this is known as ‘Darbeyn.’ There are also strings that use one usul after another. One of these consists of five usul, either 60 or 120-time, depending on which view one adopts, and this is known as ‘Zencir.’ Kücük usul in 5, 7, 9-time etc. or 10-time works such as the aksak semai, are known as ‘Aksak Usul.’ The true times that bear the name ‘aksak’ are usul in 2+2+2+3 form.