Re-diagnosis of ADHD with non-English medical record

Hi all, I'm a student moving to Kansai next April.

I've had an ADHD diagnosis since early childhood and currently take Lisdexamfetamine. I know I'll have to switch to Concerta in Japan since adult prescriptions for Lisdexamfetamine are restricted.

My main issue is that all my medical records are neither in English nor Japanese (obviously). Most advice online assumes everyone is bringing English documents. I speak Japanese, so I don't strictly need an English-speaking clinic, but I'm trying to figure out the paperwork standards before I leave.

Has anyone here successfully done the re-diagnosis/registration using European (non-English) records?

Did the Japanese clinic accept your original documents with a self-translation attached (either into English or Japanese), or were they strict about needing official/certified translations? If I can't get my current psychiatrist to write a summary letter in English, will a Japanese doctor accept the original letter with an additional self-translation?

On another note, has anyone successfully applied for an import certificate (NCD) for more than a 1-month supply of "Stimulant Raw Materials" (Lisdexamfetamine)? I'm hoping to bring a 2- to 3-month stock to cover me while I find a doctor, but I know the rules are stricter than for standard psychotropics.

Thanks for your time!

by Stein_osu