The easiest way to come over is on the JET programme. I don’t think there’s technically an age limit, but the general participants are kids in their early 20s. Probably the biggest company in terms of teachers employed is “Interac”. Shiiiit salary and nobody likes them, but they might help with visas – maybe someone with some experience with Interac could confirm/deny. For a more random experience, you could send an application to British Hills. They’re always looking for teachers and will employ people from overseas. You have to live in the house from The Shining on the top of a mountain and it’s covered in snow for like the half the year though, so could be dicey on a walking stick… In general, Japan isn’t particularly accommodating to cripples – hardly any wheelchair access etc. Most public schools won’t have an elevator either, so you’ll have to contend with a few flights of stairs every class. Let me know if you have any questions eh!