Although TV speaker announces Dadao, she is mistaken. This is Guandao (halberd) while Dadao is merely a sabre.
A guandao kwandao or kuantao is a type of Chinese pole weapon that is currently used in some forms of Chinese martial arts. In Chinese it is properly called a ??? yan yue dao ("reclining moon blade"), the name under which it always appears in texts from the Song to Qing dynasties such as the Wujing Zongyao and Huangchao Liqi Tushi. It is comparable to a European fauchard and consists of a heavy blade with a spike at the back and sometimes also a notch at the spike's upper base that can catch an opponent's weapon. In addition there are often irregular serrations that lead the back edge of the blade to the spike. The blade is mounted atop a 1.5 m to 1.8 m (5-6 foot) long wooden or metal pole with a pointed metal counter weight used to balance the heavy blade and for striking on the opposite end. The blade is very deeply curved and therefore unlike most polearms, solely useful for sweeping cuts where it relies on range and power.