https://www.thepennedsleuth.com/blog/the-black-torii

The Japanese gates, or toriis , are a common sight in Japan. They are used to mark the entrance to a holy shrine. All except one. The Black Torii, as it has become known in urban legends, marks the entrance to something else. As in all traditional religious faiths, anything different is considered sinister. However, there is no proof of anything sinister. People so far tend to lose track of where it is...or it keeps moving. Still, I had to discover the truth. Ever since hearing about the Black Torii I was obsessed with finding it.