Koyano CPA Group is a tax and accounting practice in Yoyogi with an English-language service. Its published range is advisory-heavy — corporate and personal tax returns, M&A and organisational restructuring, business succession, inheritance and estate planning, due diligence and valuation — and it also handles US tax filings, which is relevant for founders with American reporting obligations.
It holds ISO 9001 and ISO 27001 certifications, the latter covering information security, which is worth noting for a firm handling financial records. Incorporation, payroll, visa and bank account services are not mentioned, so this is a firm to engage alongside others rather than instead of them. No fees are published.