I don’t fully understand why, but these men are celebrating their beloved water source and its miraculous return by throwing water on each other in winter. And, as its a sacred ritual, they are wearing almost no clothing. It’s called Yu kake matsuri (湯かけ祭り), which basically means water splashing festival. Thanks to the hubb for forwarding this video.
We have a kind of similar event in Thailand, called Songkran (สงกรานต์). Unfortunately, men are not naked but people still splash water at themselves. Will report the event this year 😉
Please do! I am looking forward to seeing Thai festival photos!