Setsubun is a traditional day that marks the boundary between seasons — the moment when winter quietly gives way to spring. Rather than a single celebration, it represents a time of transition, once believed to be unstable and uncertain.
Before the age of modern medicine, epidemics were often explained through the presence of demons. When illness spread through a village, it was said that only the families who threw roasted soybeans to drive the demons away were spared.
In Onmyōdō, an ancient Japanese belief system, this seasonal shift was considered particularly dangerous. Around three in the morning — known as the Hour of the Ox and the Tiger — the boundary between worlds was thought to be at its thinnest, allowing harmful spirits to cross over.
So people fought invisible enemies in the middle of the night, armed with nothing more than beans.
It sounds almost humorous now. Yet this ritual still survives as Setsubun — a tradition shaped by fear, imagination, and the deeply human desire to protect health, home, and those we care about.