Out of the four folk-drama forms—kolam, sokari, nadagam, and pasu—the most highly developed and significant is the kolam, in which actors wear brightly painted and intricately carved wooden masks. The word kolam is of Tamil origin and means “costume,” “impersonation,” or “guise.” The performance consists of the masked representation of many isolated characters, such as kings, demons, deities, hunters, animals and birds, the washerman, the police constable, a pregnant woman—a British Museum manuscript concerning the kolam lists 53 such characters. The most terrifying masks are of the demons, with twisted faces, protruding tusks, and cavelike nostrils for snorting fury. The naga demon has a long, flaming, red tongue and dozens of cobras writhing around his head. Some old masks have only one large bulging eye, with a cobra hissing out from one nostril. The design of these masks uses five basic colours—red, blue, yellow, green, and black, the last two for lower-rank characters. Exaggerated comicality, distortions, bulges, nightmarish whimsy, bright colours, and the artful carving of the masks continue to entertain audiences in the 21st century.

The kolam is performed once a year for seven to 10 nights, starting at night after dinner and lasting through the early hours of the morning. The performance is generally held in the open courtyard of a house, to the accompaniment of two drummers, an instrumentalist, and a singing chorus with leader. After songs in praise of the Buddha and others (including the patron of the show), the sabhapati (master of ceremonies) describes the origin of kolam—how an Indian king’s pregnant wife expressed a desire to see a masked dance-drama and how a troupe was invited from a distant court. The sabhapati then introduces the masked characters as they enter and describes their various vocations and backgrounds.

Out of many, two plays are especially famous: the Sandakinduru Katava and the Gothayimbala Katava. The former deals with the legendary idyllic love between a half-human, half-bird couple singing and dancing in a forest. The King of Banaras comes hunting and, attracted by the beautiful Kinduri, kills her husband and makes advances to her. Rejected, he is ready to kill her when the Buddha appears and brings her husband back to life. In the Gothayimbala Katava the beautiful wife of the warrior Gothayimbala bathing in a pond attracts the attention of a demon, who falls in love with her. The enraged husband comes and chops off the demon’s head, which, because of its magical power, reunites itself with the body every time it is cut off. Finally, the forest deity comes and rescues the warrior.

The recorded history of kolam is not very old. There is only one known early eye witness account of kolam, that of John Callaway, who in 1829 published 185 verses of a play with a description of the performance and some sketches of the masks and a brief introduction concerning the masquerade. According to Callaway, the dancers did not sing. The chanters described the characters in the third person and sometimes exclaimed to draw the attention of the audience to a particular action. The earliest kolam text is preserved in the Colombo National Museum on palm leaves; another is in the British Museum inscribed on paper. The oldest printed text, edited in 1895 by A.G. Perera, is in the Colombo National Museum Library.

Masks are made of the light woods kaduru (Strychnos nux vomica) and ruk-attana (Alstonia scholaris) and after 50 years start decaying; consequently, the earlier masks are no longer in existence.

There has been an important revival of interest in drama in Sri Lanka since the mid-20th century. E.R. Sarachchandra, a scholar of traditional Sri Lankan theatre, was responsible for a major breakthrough in revitalizing and adapting for the modern stage traditional dramatic forms such as the kolam. New playwrights also helped revitalize Sri Lankan theatre, among the most significant of whom was Henry Jayasena. A producer-writer-actor, Jayasena wrote and staged plays in Sinhalese and translations of foreign plays, remaining active in his field until his death in 2009.