Javanese music, one of the richest and most distinctive of Asian musical cultures. It was and is of enormous importance in religious, political, and entertainment functions. It possesses two separate tonal systems—pélog and sléndro or salendro.Pélog contains seven tones, only five of which are used in a given composition. The intervals of pélog are unequal, and the smaller ones approximate the semitone of Western music. Sléndro is a division of the octave into five roughly equal intervals. It was believed by the Javanese to be the older system, but contemporary musicologists find evidence that sléndro was derived from pélog.Sléndro is associated with that which is masculine, and pélog with that which is feminine. The Javanese gamelan, an orchestra of tuned percussion instruments, primarily of bronze, usually accompanies a performance, particularly the Wayang Kulit (shadow puppet plays). It flourishes today in Bali, where it was introduced in the 15th cent. by Hindus escaping from the Muslim invasion of Java. Balinese gamelan is distinct from Javanese in that it is played much faster and is brighter tonally. The term gamelan includes percussion orchestras of varying function, style, size, and composition. The set of instruments known collectively as gamelan increases in value with age and with the concomitant stabilization of its individual sound. Gamelan instruments include gongs, drums, xylophones (gambang kayu), bamboo flutes (suling), and string instruments (rebab). A complete double set, or sapangkon, half tuned to pélog and half to sléndro, may number as many as 80 separate instruments. They are played two ways: according to a subtle, flowing, quiet manner associated with singing and gentle dancing, and according to a powerful, louder manner associated with heroic dance. A fixed melody is the basis for complex vocal and instrumental improvisation. The archaic gamelan, no longer heard widely in Java, is best studied in Balinese music.

See J. Kunst, Music in Java (2 vol., 1949); D. A. Lentz, The Gamelan Music of Java and Bali (1965); S. Walton, Mode in Javanese Music (1986).