Kemanak is a banana-shaped idiophone

Idiophone

An idiophone is any musical instrument which creates sound primarily by way of the instrument's vibrating, without the use of strings or membranes. It is the first of the four main divisions in the original Hornbostel-Sachs scheme of musical instrument classification...

 used in Javanese gamelan

Gamelan

A gamelan is a musical ensemble from Indonesia, typically from the islands of Bali or Java, featuring a variety of instruments such as metallophones, xylophones, drums and gongs; bamboo flutes, bowed and plucked strings. Vocalists may also be included....

, made of bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

. They are actually metal slit drum

Slit drum

A slit drum is a hollow percussion instrument, usually a log drum of bamboo or wood, that is made with one or more slits in it. Most slit drums have three slits, cut into the shape of an "H". If, as is usual, the resultant tongues are different lengths or thicknesses, the drum will produce two...

s. It is stuck with a padded stick and then allowed to resonate. It has a specific pitch, which can be varied by covering the slit, but it is not matched to the other instruments of the gamelan. They are usually played in pairs, although they can be played in sets of four as well. They are used to accompany the bedhaya

Bedhaya

The bedhaya is a sacred ritualized dance of Java, Indonesia, associated with the royal palaces of Yogyakarta and Surakarta...

 and serimpi, female court dances.

Kemanak is also a style of gendhing

Gendhing

The gendhing is a class of gendhing structures used in Javanese gamelan music. Gendhing can also be used to refer to gamelan compositions in general....

 which includes, in addition to kemanak, only colotomic instruments, a kendang

Kendang

Kendhang is a two-headed drum used by peoples from Maritime Southeast Asia....

, and a sindhen

Sindhen

A pesindhèn is a female solo singer who sings with a gamelan. They may perform in unaccompanied music, dance, or wayang performances....

.

In the region of Cirebon

Cirebon

Cirebon is a port city on the north coast of the Indonesian island of Java. It is located in the province of West Java near the provincial border with Central Java, approximately 297 km east of Jakarta, at .The seat of a former Sultanate, the city's West and Central Java border location have...

 on the Northwest Coast of Java

Java

Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...

, Kemanak are played in pairs by striking one against the other in a repetitive fashion. Unlike in Central Java

Java

Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...

, Kemanak in Cirebon aren't reserved for specific performance idioms and are considered indispensable in the standard Gamelan

Gamelan

A gamelan is a musical ensemble from Indonesia, typically from the islands of Bali or Java, featuring a variety of instruments such as metallophones, xylophones, drums and gongs; bamboo flutes, bowed and plucked strings. Vocalists may also be included....

repertoire.