I cannot say this firmly enough:

Find a specialist.

Ideally, you want to find a specialist recruiter who is themselves Japanese and lives in Japan but who has lived and worked in the UK, EU or US. The Japanese employment market is strikingly different to pretty much anywhere else in the world and is not to be entered into without expert guidance.

If you are establishing a trading entity in Japan, you have, I would very much hope, engaged a Japanese legal firm to assist you with the process. They should be your first stop when seeking a referral to a reliable employment agent or agency to assist with the sourcing and onboarding of key staff in Japan.

In reply to Robey:

Thanks Robey. Yes we have engaged a legal firm in Japan.

Hi Kelly,
I don't know your industry and I would agree that your legal firm is a solid first step; just here to tell you that if you prefer an additional contact, I can provide you with the name of a TA lead who is considered the expert in the global TA-Brainfood community for doing recruiting in Japan, and he's been very extrovert, i.e. available and glad to provide insights for anyone looking to recruit in Japan.
I won't put his name here cause I am not sure this would meet the community guidelines, but let me know if you want it and I'll give you his LinkedIn profile to connect.
Thanks
Calliope

In reply to Calliope:

Hi Calliope - thanks for that. If you were able to message me with the contact that would be great.

In reply to Kelly Hodkinson:

Just did it, Kelly.

Thanks