(VOVworld) – Twenty-six art troupes from 12 provinces are participating in the National Ca Tru (ceremonial singing) festival 2014, which opened in Hanoi on Tuesday. The 4-day festival is part of Vietnam’s commitment to preserve and develop the singing style which was recognized intangible cultural heritage in need of preservation by UNESCO in 2009. At the opening ceremony, Deputy Minister of Culture, Sports, and Tourism Vuong Duy Bien said the UNESCO recognition is an honor and a challenge for Vietnam in preserving the art form.