The first recorded ca tru album (an ancient genre of chamber music featuring female vocalists) has just been released as part of an extensive effort to promote the Northern musical genre.

The album, entitled Ca tru – singing house, features famed singer Pham Thi Hue and her teacher, the 88-yeard-old dan day player, Nguyen Phu De.

The pair recorded six songs, all of which are based on 19th century Vietnamese poems.

According to Hue, the idea to release the album came to her five years ago, when two famous ca tru artists, Nguyen Thi Chuc and Nguyen Phu De, agreed to take her on as a student.

Hue was already a famous commercial artist when she approached the pair in 2006, the same year that De was granted the “Folk Artisan” title by the Vietnam Folk Art Association.

The local star spent the next three years helping develop the Thang Long Ca Tru Theater in Hanoi.

After the theater opened and began offering classes and shows, De and Hue spent an entire year trying to replicate the intimate sounds of ca tru - which had never been recorded before.

“The album is what I will leave behind when I pass away in the hope that it will be useful for those who want to learn and preserve the art,” said De, who is now 88 years-old.

In the meantime, Hue and others artisans perform ca tru every Saturday night at the Thang Long Ca Tru theater.

Each one-hour show is divided into two parts, including a 45-minute performance and a 15-minute discussion about the art in both Vietnamese and English. Tea and sugar coated-lotus seeds are served during the performance.

“Tickets are available for US$10,” said Pham Thi Hue. “All proceeds will go to promoting the art. I hope ca tru will be warmly welcomed by foreign audiences.”

In 2009, the genre was recognized by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as a world intangible cultural heritage in urgent need of preservation.

Ca tru, like many ancient and highly developed arts, has many forms. However, the most widely known and widely performed iteration involves only three performers: a female vocalist, a lute player and a spectator (who also takes part in the performance).

The female singer provides the vocals whilst playing her phach (small wooden sticks beaten on a small bamboo platform). She is accompanied by a man who plays the dan day (a long-necked three-string lute).

The spectator (often a scholar or connoisseur of the art) strikes a trong chau (praise drum) in praise or disapproval of the singer’s performance, usually with every passage of the song.

The way in which he strikes the drum shows whether he likes or dislikes the performance, but he always does it according to the beat provided by the vocalists’ phach percussion.

New observers to the art often comment on how strikingly odd the vocal technique sounds, but it is the vocals themselves that make ca tru unique.