A cool demo of some fighting techniques. Peasants couldn't have swords, so they took farming implements and made partial arts around them. This is a demo of a non lethal version of a real weapon. The head strike would have been lethal, and the arm strike bone breaking. The actual swinging part being spiked and weighted. Every strike would have been disabling.
I've not watched the video due to a slow phone connection today but from the title image it seems to be kendo.
This is not a style in particular but rather a combination of several traditional styles including iaido strikes, and ninjutsu weapons. If you are interested in martial arts that involves weapons, check out Kali Eskrima from the Philippines, very effective in real life situations.
The chain and sickle was a favoured weapon of ninjas, who were typically disguised as farmers (though they were typically spending their time making gunpowder).
