Abilities is a company that deals with import wheelchairs and has a shop in Hiroshima. They are your best bet but likely don’t have English speaking staff, so best to get your hotel to call. Here is their info:

https://www.abilities.jp/abilities_group/office/hiroshima

Can you please tell us the type and make of your wheelchair?

Sounds like a good plan. Even if it isn’t a note from the doctor, thinking of some things you might expect to say regularly (“I cannot walk and need the scooter for mobility because of a disability” etc) and have them ready to show can be helpful.

Hi,

Those words are:

Crustacean is “Kokaku-rui”

Seafood in general is “Gyokai-rui” but that includes fish etc

I’m not sure if you saw this, but hopefully it will be an encouragement:

https://www.accessible-japan.com/go-global-traveling-in-japan-with-a-mobility-scooter/

Perhaps the author @gobyscooter can reply.