Japanese festival

This week I found a video of the strangest thing I've seen in a long time...
I found a video about a Japanese festival, which I first thought wasn't real. But then I realized that they have many interesting festivals and celebrations, so I guess this was just another one of them.

This festival is held in the city Kawasaki in april, so it's too bad that I'm going to Japan in May :-P

Try to guess what the festival is about. Enjoy the video and feel free to comment below! :-)