The Room Inside of the Room is an artwork by Oscar Oiwa that you can see on Ogijima. No, it’s not what you think, the picture’s orientation is indeed correct.
Fun fact: last year, I got to write a few articles in a few magazines about the Setouchi Triennale 2016. Very often, I also provided pictures, and very often I provided pictures of this artwork. When the article was sent back to me to double-check before publication, the picture was very often turned on its side, and the person in charge of the layout was often confused when I told them that they made a mistake.
It’s a permanent artwork on this island, and as such it’s open every week-end and holiday from mid-March to early November, as well as Fridays too in July and August. Do not miss it when you visit Ogijima.
If you want to know more, there is a video of Oscar Oiwa introducing his artwork on the blog.