The Ho Su Cha (Khu Su Cha) Tet festival of the Ha Nhi people in Dien Bien is the most important traditional festival of the year, deeply rooted in the cultural identity of one of the ethnic minorities living in the far west of the country.

The Ha Nhi people (also known as U Ni, Xa U Ni) consist of three local groups: Ha Nhi Co Cho, Ha Nhi La Mi, and Ha Nhi Den. In Dien Bien province, the Ha Nhi people live concentrated in four border communes of Muong Nha district: Sin Thau, Sen Thuong, Chung Chai, and Leng Su Sin (now Sin Thau commune, Muong Nha district), mainly belonging to two groups: Ha Nhi La Mi and Ha Nhi Co Cho. According to custom, the Ha Nhi Co Cho celebrate Tet on the Day of the Tiger, while the Ha Nhi La Mi celebrate Tet on the Day of the Dragon of the last month of the year according to their own calendar, differing by about 3 days. Tet takes place after the harvest, and is a time for family reunions, showing filial piety to ancestors, and strengthening village solidarity. The Ho Su Cha Tet lasts for 3 days, with many traditional rituals. On the first day, families make glutinous rice balls (Cha Le) from upland rice to offer to their ancestors. The offered balls must be large and round, showing respect and reverence. After the offering ceremony, the family slaughters a pig – a mandatory offering during the Ha Nhi New Year – and also uses the pig's liver for divination to predict good fortune and livestock farming in the new year. The second day is the day of pounding sticky rice cakes (Ga Ba), followed by festivities, visits, folk singing, traditional dances, and folk games. On the third day, the New Year atmosphere remains vibrant with gatherings and exchanges before the New Year season concludes. The Ho Su Cha New Year possesses a warm, simple beauty but is rich in humanistic values, reflecting the principle of remembering one's roots, the rich spiritual life, and the unique cultural identity of the Ha Nhi people. Today, the Ha Nhi New Year has become a highlight of cultural tourism in the border region, attracting tourists to experience traditional rituals, local cuisine, and folk games, combined with exploring A Pa Chai – the westernmost point of the country, leaving unforgettable impressions of the people and culture of the mountainous Dien Bien region.