When I emailed the govt section dealing with special licensing they basically said that wheelchair was okay but I recommend you email them to confirm this for yourself.

they are particularly interested in the medications and medical supplies and equipment. I had to list out each item and get approval. I also need a doctors letter to prove the disability.

Hi, I live in Japan and use a foreign made power wheelchair and before moving here I brought my wheelchair numerous times. So, there should be no problem there.

Scooters on the other hand, while they don’t need a license, they can be a bit more limited in where you can use them.

You can read more here: https://www.accessible-japan.com/mobility-scooters-japan/

Thank you both!