杉山会計事務所
Sugiyama Accounting Office
Two generations of tax practice in Kagurazaka
Sugiyama Accounting Office is the common name for the joint practice of two licensed tax accountants and certified administrative procedures legal specialists, Yasuo Sugiyama and Yasuhiko Sugiyama. The formal names of the two practices are Yasuo Sugiyama Tax Accountant Office and Yasuhiko Sugiyama Tax Accountant Office.
Born and raised in Kagurazaka. Since my father's generation, our family has run a tax office here for two generations.
After working as a product manager for Office and PowerPoint at Microsoft, I studied in China and opened a tax office in 1998. I served as a corporate auditor of Tully's Coffee from its founding days, seeing firsthand how a business gets off the ground. Since then I've served as an executive at venture companies while working on matters involving IT companies, IPOs, and public company board roles. Today I continue to think about and advise on AI and DX, crypto assets, working abroad, and the next careers of business owners and athletes. I hold a patent for remote-work environment setup and management, and have authored 31 books to date.
For more than fifty years — from Japan's era of rapid economic growth, through the bubble years and the decades that followed — Yasuo Sugiyama has worked on the front lines of tax and accounting. He has spent a good part of his life alongside many clients, and seen them go on to their next stages.
Experience that knows firsthand the economic climate of each era is a great asset of this office, one that AI cannot replace. And he has carried the office forward to the next generation.
Tax consulting can't be separated from a company's or an individual's situation. What matters changes depending on the stage of the business, the owner's role, family, assets, where you work, and what you want to do next.
From a computer-loving student, through the internet's rise at Microsoft, to introducing IT and DX as a tax accountant — now working with AI at the center. From cloud-based accounting and tax work to AI agents, I offer the exact systems I use myself.
I've supported three clients through to IPO. At Microsoft, I handled many stock option filings back when they were still uncommon in Japan. Beyond the tax treatment of stock awards, ESPPs, and RSUs, I can also advise on crypto asset management and operations, not just taxation.
For over 30 years I've traveled between China and Japan, watching its growth firsthand. While I'm not fluent in Chinese, decades of relationships have given me a real understanding of the mindset and business customs. I support business owners from China who are starting or continuing a business in Japan.
Once people build up assets, I'm often asked, "Is it really fine to leave everything in Japan?" Personally, I don't think that's the best answer. I keep exploring possible destinations, mainly across Asia. I support working and living abroad from many angles, not just tax.
Second-career planning is essential for athletes. In an age of 100-year lifespans, more office workers are finding that retiring at 60 is too early. With a tax perspective in mind, I work with you on asset planning for changing income, and options like incorporation or independence, as we think through your next career together.
I answer questions people often ask me in a question-and-answer format. Here are three that show how our office works.
I don't think it can be measured by credentials or track record alone. What matters most is whether the tax accountant truly understands how you think about running your business. And beyond that, I'd say what matters even more is whether the chemistry is right — whether you simply get along. More than industry-specific knowledge, it's about finding someone who understands your way of thinking and can translate it into tax and accounting terms. I'd encourage you to choose a tax accountant who's willing to walk through that process with you.
To be honest, I don't think the services themselves — bookkeeping, filings and so on — differ much from one accounting firm to another. What makes the difference is the people involved: their experience, their abilities, and their personality. That's exactly why I've deliberately kept the office from growing large, so that quality doesn't slip. Routine day-to-day work is handled by our staff. And whenever something comes up — a problem, a management decision you're wrestling with, anything you'd like to talk through, business or personal — you can bring it straight to me, right away. That closeness is possible precisely because we're not a large office, and I value it.
I'm convinced AI will fundamentally change how people work. Routine tasks will keep disappearing, and a person's value will increasingly come down to whether they can raise real questions and genuinely think. I believe the same is true for tax and accounting. As AI takes over routine work, tax accountants should be freed from that work and become someone who engages more deeply with what a client truly wants to do and express. Having watched the early days of the internet firsthand, I feel this shift isn't just about adopting a new tool — it's a transformation in the way we work.
An essay drawing these thoughts together: Beyond DX — The Tax Accountant in the Age of AIX
