Freelancing in Japan as a side job while on an Engineer visa — best way to receive payments from Europe / Overseas ?

Hello,

I’m currently working full-time in Tokyo as a software engineer (正社員) under an Engineer/Specialist in Humanities/International Services visa. My company has given me permission to do some freelance work on the side, and as far as I understand, since the freelance work is in the same field (software development), it should be allowed under my current visa category — so I don’t need a separate permit from immigration (please correct me if I’m wrong).

I’m planning to do around 15 hours per week of freelance work for a European client, who will pay me in euros.

I’ll be registering as a sole proprietor soon.

I’d really appreciate some advice:

• What’s the best way to receive payments from Europe? I’m thinking of using Wise, and as soon as I receive the money, transferring it to a Yuucho account I opened when I first arrived in Japan (I currently only use it to pay rent by manually depositing money from time to time). I have another account with a different bank that I use more often and where I receive my full-time job salary.
• Any tax or accounting tips for handling euro payments (conversion rates, documentation, etc.)?
• If I use Wise, can I still connect it to Freee for bookkeeping, or would it be easier if payments go directly into a Japanese account?
• Any general tips on bookkeeping so I can properly file for the blue tax form ?

Thanks a lot for any advice or experiences you can share!