Hi, so I’m here in Japan as we speak. I’m using a WHILL mobility scooter. I’ve used the Shinkansen twice to Osaka and I have been advised to book an “Multi Purpose Room” on the train to store the scooter for the journey. This is okay if you have people travelling with you, I am lucky to have my family with me. The staff were extremely accommodating and helpful and the scooter fitted perfectly into the little multi purpose room. I hade to disengage the brakes and manually roll it into this tiny small room. They measured the scooter and it was refused for a disability/accessibility space. However we managed in the end. The Shinkansen is wonderful, so peaceful, quiet and comfortable. Hope this helps.