There could be a fanfiction where Harry is abandoned near a Japanese magical school. The students there are initially suspicious of him but then they realize his potential. He might form new friendships and rivalries, and together they explore the secrets of the Japanese magical world that are intertwined with the natural beauty of the country, such as magical forests and hot springs with special properties.
One interesting fanfiction could be where Harry Potter is abandoned in a small Japanese village. He might discover the local magical traditions that are different from the British ones. Maybe he meets a kind Japanese wizard family who takes him in and he has to adapt to their way of life, like learning about Japanese magical creatures and spells.
In some fanfictions, Harry's abandonment in Japan could lead to a complete change in his magical identity. He could be found by a group of Japanese witches and wizards who are on a quest against dark forces in their own land. Harry then becomes part of their mission, using his unique skills from Hogwarts while also learning new Japanese magic. This could involve battles in ancient Japanese castles or shrines that are now home to powerful magical artifacts.