It’s called Toshimaen the amusement park that has closed this summer to make place for a new Harry Potter theme park that will open in 2023. The Toshimaen park had been opened since 1924 and this is a major change in its long history.
From what we can gather it will be probably similar to the Warner Bros one in London. According to the press release you will be able to explore the iconic movie sets that were actually designed and built by the creators of the Harry Potter series. You will see the original costumes and props and you will be able to immerse yourself in many scenes of the films. It is not expected to be a traditional theme park with rides, but more like an Harry Potter experience.
Not everyone will want to travel all the way to Japan to see this new theme park, although many serious and committed Potterheads might.