This is Niihama Taiko Festival in Niihama City, Shikoku region, which is held every October. The holy festival enjoys more than 400 year history. It is a ritual to thank for the bountiful harvest, to pray a big catch, and sea safety, and it is said that there were many fishermen in the community there in the Edo period who became radicalized. More than 50 floats participate, (every town has its own float, portable shrine, which costs over 2 million US dollars each) and compete with other towns for the luxury and strength of the floats. The drummer on the float never stops and the carriers of the float, who are volunteer citizens representing each community, fight with the opponents to destroy and protect the floats. If the float is destroyed or the drummer stops beating the rhythm, it will be the end, but this does not mean defeat; in the ritual, the loser can also receive God’s blessings. It’s very very dangerous but not uncommon to see such dangerous festivals in Japan. This festival is quite famous as one of ‘three biggest fighting festivals in Japan’ though. Sometimes we see the dead during the festival but the police do nothing because this is the quite sacred festival, the tradition and part of Japanese culture. This is a men's festival and women dress up and watch the fight.
So its called the Niihama Taiko Festival, often also "The Man Festival"(男祭り), which is an festival dedicated to a good harvest. They are building these floats, carrying them around the city and up to different shrines, for many hours a day, drinking drinking a shitton of sake. Occasionally they ram into another groups float with their float, with an ensuing melee which often destroys one or both of the floats as a end result. Just man things :D
