"Hangon" ritual--supposedly also known as "Calling Back of the Spirit"
I'm looking for any information on a Japanese ritual called "Hangon"--supposedly for reviving the dead. Of course it's a bit fictional, but I want to know whatever there is about it. I've only seen very little information about it in connection to Rumiko Takahashi's Mermaid Saga, mostly because typing "hangon" into a search engine just assumes you forgot a space. I'm writing something centering a lot on Japanese occult folklore, and this would be a great addition.