There are three main theories why the naginata was made. One of the most spread is the belief that naginata evolved from a farming tool used for chopping. The tools were made as long staffs with sharp stones attached to one of the ends. The tool was used in the 3rd century B.C. Later, the stones were replaced with metal pieces. Thus, when the crops and lands of the farmers were under attack they defended it with their farming tools, which proved to be effective weapons and were later improved.. 