What is the Dadao sword?
This sword is a machete-like sword that was made famous by the Chinese in world war 2 against the Japanese.
Games and anime with the Dadao
this is an anime where two bounty hunting (Johnny and Yosaku) has dadao. There are in the Baratie arc and Arlong Park arc.
Shadow fight 2 & 3
This is a 2D mobile fight game set in feudal Japan. The dadao is one of many other weapons in shadow fight also it is now on the Nintendo switch.
The Dadao is not in the Original Fallout 4 but there is a mod to get it in the game.