Boeing Knife it is for thick jungle for cutting vines. This is why it is covered so it does an opposite of Samurai sword it allows with harder stroke to be more pin pointed and then slide… rather the end of the stroke so on to slide though more.
Mostly south east Asia types use it was created off a sickle and then adjusted for this purpose. It worked as a duel purpose in many cultures. It is one of the large knifes and one of the best survival knifes.