Ban Soc is the Calendar Delivery Rite taken place every lunar year-end under the Nguyen Dynasty. The former Vietnamese gave priority to the agricultural economy, hence the calendar was of great significance to them. The calendar was used to be in right track with the change of weather and natural catastrophes. Every year, after the Dynastic Observatory Department finished compiling the calendar, the dynasty carried out the Calendar Delivery under the supervision of a mandarin from the Ministry of Rites and another from the Observatory Department. The calendar was for the sent to the Royal Family, Mandarins working right at the Capital City, Mandarins at localities, and  finally to the mass.

The rite had been operated at the yard of Thai Hoa Hall. Until 1841, Emperor Minh Minh Mang had it done at Ngo Mon Gate.

Thua Thien Hue Province has always been the first to organize this contemporary festival style of national and international levels. For over 22 years, Hue Festival has become a highlight in the world festival system. The role and importance of Hue Festival has been more important in Hue generally and Hue tourism as well as economy particularly. For such a significance, this event is of great concern of Thua Thien Hue leaders.