We help businesses succeed with tax support specializing in sole proprietorships and English-language support.

Experience reliable and trustworthy tax and business support at Tenmusubi Certified Public Tax Accountants' Office.


small business owner

targeted at individuals

Tax and accounting support specializing in sole proprietorships

English Support

Tax consultation and support services for individuals and corporations in English

Lectures and Writings

Tax professional speaking, writing, and interview services

corporate tax


Solving corporate tax and management issues

Office Features


We serve many clients, including sole proprietors and English-speaking clients (individual and corporate). We can also provide flexible services such as spot consultations, seminars, and writings to meet the needs of our clients.

Commitment to the Latest Technology02

Our firm is proactive about information technology. For example, we offer cloud accounting and electronic bookkeeping services, use web conferencing (ZOOM) to serve clients in remote locations, and are researching the use of ChatGPT in our operations.

Solid expertise and experience 03

Our principal tax accountant, Kojima, has extensive knowledge and experience in a wide range of business support services and consistently provides services such as small business sales and stock valuation of family-owned companies for a transparent fee.

Introduction of Representative Tax Accountant Akihiro Kojima

I am Akihiro Kojima, the principal tax accountant of our firm. He has a wide range of knowledge and experience in dealing with sole proprietorships, English-speaking clients (individual and corporate), and Japanese corporations. He is well versed in IT, enabling him to provide services utilizing the latest technology and English. This allows customers who are not fluent in Japanese to receive support with confidence.

We have extensive experience in back-office operations and can assist management from many angles. We strive to provide services that are more in line with your needs, without being overly technical in terminology.

We provide daily information on our blog, Twitter, and YouTube. If you have time, please take a look at our outgoing information.

Application and prior consultation


Applications for services can be found on the Introduction page of the various services. Please apply from the service page of your choice.

prior consultation

If you have any questions or concerns before applying, please get in touch with the following pre-consultation desk. Please note that we do not accept solicitations, sales pitches, YouTube or TikTok management on behalf of our clients or tax accountant referral agencies.

If there is anything you would like to discuss or ask about, please indicate here.
Purpose of use of personal information
  • Self Magazine Shipping
  • Contacting you in response to your inquiry
  • ・Contact us when we provide services tailored to your needs.

Customer Testimonials


Mr. T (sole proprietor)

Dr. Kojima's knowledge of taxation really put my mind at ease. He explained everything in a way that was easy to understand and helped me to accurately prepare my personal business tax affairs. I am able to choose the way to do things based on my business, rather than "sort of this way. I would like to ask for your help in the future!

Mr. B (individual, English speaking)

I was looking for a tax accounting firm that could provide assistance in English, and I found Dr. Kojima. He was very knowledgeable about the Japanese tax system and explained it to me in English in detail.

Mr. Y (IT-related company)

I consulted with Dr. Kojima, who is also strong in IT, because I have an IT-related business. He gave me advice on efficient management and cost saving, and I am very satisfied with his advice.

Mr. L (Corporate, English speaking)

For our foreign company, Dr. Kojima provided support on Japanese tax matters. He is a reliable partner with smooth communication in English.

Mr. K (Manufacturing industry)

I consulted with Dr. Kojima to streamline my back office operations. We were able to consult with him on many aspects and recently had a helpful discussion about advertising. He suggested appropriate solutions, and the company's operations have become smoother. I am grateful.

Mr. S (design office)

By consulting with Dr. Kojima, who has extensive knowledge not only in taxation but also in IT-related matters, we were able to improve the efficiency of our business and save expenses. His easy-to-understand explanations allow us to rely on him with peace of mind.

case study


01 Advisory Cases for Sole Proprietors

IT Consultant Management Improvement

Our firm provided an analysis of the business situation and tax planning advice to a sole proprietorship of an IT consultant. As a result, the business's profit margin improved as a result of the cost savings and reduced tax burden.

02English Language Support (Individual) Cases

Tax support for Non-Japanese freelancers

We assisted a foreign freelance designer in filing tax returns in Japan, explaining the necessary procedures and tax-related precautions. As a result, we facilitated a smooth tax filing process.

03English Support (Corporate) Cases

Tax Preparation for Foreign Companies

We assisted a foreign company with tax planning and optimization in Japan. We also pointed out areas where international taxation was relevant and realized tax reduction measures.

04Stock valuation case

Stock Valuation of Small and Medium Enterprises

Stock price is not considered in small and medium-sized enterprises. Upon request, we calculated the stock price as a formal price, not an estimate.

05The Case of the Lecture

Tax Lecture on Electronic Bookkeeping Law Measures

The lecture included a short presentation on measures for the Electronic Bookkeeping Law, which has become a hot topic in recent years, and how it can be used to promote sales of IT equipment. Not only taxation, but also market sense was applied.

06Intermediary case of business sale

Asset optimization through business divestitures

For an individual who was considering selling his business, we assisted him in setting an appropriate price and selecting a buyer. As a result, the sale of the business proceeded smoothly, and business succession and asset optimization were realized.

07Land case of forgotten registration

Application of special provisions for real estate

We discovered a registration error on a piece of land that we wanted to dispose of. We examined the possibility of reducing the amount of tax due on the land and guided the client through the necessary procedures and steps to successfully reduce the amount of tax due.

Frequently Asked Questions

Please open this page to check.
What services are available for sole proprietors?

For sole proprietors, we offer a wide range of services including tax advisory services, tax return support, accounting and financial advice, and tax reduction strategies.

What services are available in English?

For non-Japanese clients, we provide services in Japanese and English, including advice on establishing a business in Japan and tax procedures, consultation services for individual or corporate matters in English, and international tax planning.

My tax return is due soon, can I consult with you?

Regardless of the deadline for filing tax returns, we will respond to your situation. However, we recommend that you consult with us well in advance.

Do you accept requests to speak or write?

Yes, we are also available for speaking and writing engagements on tax and management matters. Please feel free to contact us.

I was contacted by a tax audit. How should I respond?

We also provide support for tax audits, even if you are not an advisor. Please contact us and let us know your situation.

I am considering incorporation, can I consult with you?

Yes, we also provide consultation on incorporation. We can also work with you to determine whether it is advisable to incorporate based on past financial data and other information. We will propose appropriate incorporation procedures and tax planning.

Is online consultation available?

Yes, we offer online consultations. We utilize telephone and video calls to serve our remote customers.

Can I consult with you regarding business succession or the sale of my business?

Yes, we also provide consultation on business succession and business sales. We can provide services such as tax and valuation optimization and assistance with financing.

Do you accept just income tax and consumption tax consultations?

Yes, we can provide consultation on income tax and consumption tax issues alone. Single consultations are also welcome, so please feel free to contact us.

Do you also offer IT-related services?

Yes, we also provide IT-related services. We can help you improve your business management by utilizing IT, such as streamlining accounting and finance, and supporting the introduction of cloud accounting.

How are service fees determined?

Service fees vary depending on the nature of the consultation and the scope of services. Please refer to the rates listed on this page first. We will also be happy to provide a quote for items not listed. Please let us know your specific needs.

Can I consult with you outside of business hours?

Consultations outside of business hours are also available by appointment in advance. We strive to be flexible and accommodating to our customers' needs.


We are a member of the "Association of Micro M&A Professionals" and aim to work with M&A professionals to provide more excellent value to our clients. Mergers and acquisitions are not only an option for business liquidation but also an option that can be taken by small and medium-sized companies that are short of successors.
We use Yayoi and Freee accounting software. In addition to installed accounting software, we employ cloud accounting software to meet the needs of our clients. We also have partnerships in labor management such as Jobcan.


In addition, we aim to cooperate with the following companies and organizations as future partners

  1. Accounting and labor software companies: Partnering with cloud accounting software can provide customers with more efficient accounting processes.
  2. Tax and labor consulting firm: We work with tax and labor professionals to provide comprehensive services to our clients.
  3. Management consulting firm: we will work with business strategy and marketing experts to help our clients grow their businesses. We will also cooperate with M&A related to business succession.
  4. International tax and law firms: provide expertise in foreign tax and legal systems to clients with international operations.

For partnership information, please get in touch with us at

→ Make a "Partnership Inquiry

Please note that we do not accept solicitations or sales pitches.

Purpose of use of personal information
  • Self Magazine Shipping
  • Contacting you in response to your inquiry
  • ・Contact us when we provide services tailored to your needs.