Kaidan is a Japanese word that means "ghost story" or "scary tale". Just like how you might tell spooky stories with your friends around a campfire, the Japanese have a tradition of sharing scary stories too. These stories often include ghosts, monsters, and other creepy creatures. People would sit around and listen to these stories to see who could get the most scared. Sometimes they would even go to places that were believed to be haunted, like old abandoned houses or forests, to try and experience ghosts and other supernatural things for themselves. Kaidan is still enjoyed today in Japan, and people continue to share and enjoy spooky stories.