Castanets, also called clackers or palillos, are a type of percussion instrument (idiophonic) used in Spanish, Calé, Moorish, Ottoman, Greek, Italian, Mexican, Sephardic, Portuguese, Filipino, Brazilian, and Swiss music. In ancient Greece and Rome, a similar instrument called the crotalum was used.

The instrument is made of two concave shells connected by a string at one edge. They are held in the hand and used to create rhythmic clicks or a rapid, rattling sound. Traditionally, they are made of hardwood like chestnut (called castaño in Spanish), though fibreglass is now commonly used.

When played, a musician usually holds two pairs of castanets, one in each hand. The string is looped over the thumb, and the castanets rest on the palm with fingers curled to support them. Each pair produces a slightly different pitch. The lower-pitched pair is used to mark the beat with joined fingers, while the higher-pitched pair is used for variations, including sounds that resemble a rattle.

The origins of castanets are not certain. However, the practice of clapping sticks together to accompany dancing dates back to ancient times and was used by Greeks and Egyptians. Many sources suggest the Phoenicians, who traded across the Mediterranean about 3,000 years ago, helped spread the instrument, as they had strong trade links with what is now Spain. Some believe castanet-like instruments existed in Ancient Egypt, made of wood, ivory, or metal. By 200 BC, Ancient Romans encountered the instrument among the Iberian people in Hispania. It later became an important part of folk music in Spain. In modern times, instruments like bones and spoons used in Minstrel shows and jug band music are also considered similar to castanets.

During the Baroque period, castanets were often used in dances. Composers such as Jean-Baptiste Lully included them in music for dances featuring Spaniards (Ballet des Nations), Egyptians (Persée, Phaëton), Ethiopians (Persée, Phaëton), and Korybantes (Atys). They were also used in dances with characters like demons (Alceste) and nightmares (Atys). A ballet from 1669, Flore by Lully, mentions that "the Africans, inventors of castanet dances, enter with a more cheerful air."

Rarely, castanets are given a solo role in music. Examples include Concertino for Castanets and Orchestra: Three Anecdotes (1977) by Leonardo Balada and Conciertino für Kastagnetten und Orchester by Helmut M. Timpelan, performed with castanet virtuoso José de Udaeta. Other works include Toccata Festiva for Castanets by Allan Stephenson and arrangements performed by Sonia Amelio as a soloist.

In the late Ottoman Empire, performers called köçeks danced and played percussion instruments, including a type of castanet known as çarpare. These were later replaced by metal cymbals called zills.

Castanets in Spain

Castanets are often used in Spanish folk music and dances, such as the Jota, a music/dance that may have originated in Aragón, and the Fandango. They spread to other areas in Spain, including central and southern regions. Castanets are also used by singers and dancers in the flamenco genre, especially in some types of flamenco (Siguiriya and Fandango-influenced ones), and in other dances in Andalusia, such as the Sevillanas folk dance and escuela bolera, a ballet-like dance form. The name (Spanish: castañuelas) comes from the word "castaña," which means chestnut, and the name is a smaller version of that word. In Andalusia, they are usually called "palillos" (little sticks), and this is the name used in flamenco. In parts of southeastern Spain, like Murcia, castanets are called "postizas" and are played in a slightly different way (hooked over other fingers).

Castanets are used in famous operas, such as Georges Bizet’s Carmen. They also appear in the "Dance of the Seven Veils" from Richard Strauss’s opera Salome and in Richard Wagner’s Tannhäuser. A special type of castanets made of metal is used in Darius Milhaud’s Les Choëphores. Other examples include Rimsky-Korsakov’s Capriccio espagnol, Ravel’s Rapsodie espagnole, Francis Poulenc’s Concerto for Two Pianos and Orchestra in D minor, and Karl Jenkins’s Tangollen.

Castanets also appear in the music of Naples, showing Spanish influence. This was recorded by Athanasius Kircher in his work called Tarantella Napoletana (tono hypodorico).

Mounted castanets

In orchestral or jug band settings, castanets are sometimes connected to a handle or fixed to a base to create a pair of machine castanets. This design makes them easier to play but changes the sound, especially for machine castanets. A roll can be produced using any of the three ways castanets are held. When held in the hand, they are struck against the fingers and palm. When held on sticks, a common method involves bouncing them between the fingers and the player's thigh. For machine castanets, a less satisfactory roll is created by quickly alternating the two castanets with the fingers.

Handle castanets

Handle castanets were created for use in orchestral music. A pair of castanets is attached to the end of a straight wooden stick. They help create long, continuous sounds, especially loud ones, when played on the instrument.