Toro nagashi (灯籠流し) literally means "flowing lanterns." It is a ceremony in which paper lanterns are released down a river or into the ocean, often performed on the last evening of the summer Obon season, when it's believed that the spirits of one's ancestors return to the living world. The lanterns are said to guide the spirits back to the other world as they float away.

Some well-known toro nagashi festivals include the Arashiyama Toro Nagashi Festival in Kyoto and the Asakusa Toro Nagashi in Tokyo, both held in August. However, toro nagashi ceremonies are also held on other occasions, and the Kaga Yuzen Toro Nagashi, featured in the video above, actually occurs the night before the Hyakumangoku Matsuri, the largest festival in Kanazawa, which takes place on the first Saturday in June.