Filing a Business-Start Notice Does Not Make You a Blue-Return Filer. An Employee's First Side-Business Year, Doing Japan's Blue Tax Return with Claude
This year I filed a notice of business commencement. I have a day job and build apps with AI on the side. At the end of Part 1, I promised a separate article on how to file Japan's blue tax return (aoiro shinkoku). This is that article.
The first thing I learned is that the business-start notice and the blue return are separate procedures. The blue return needs its own approval application, and if you miss the deadline, that year cannot be filed as a blue return.
Along the way I realized most of the bookkeeping can be handed to Claude: reading receipts, drafting journal entries, calculating depreciation, and matching the books against statements. I built a flow that leaves only judgement, filing, keeping the originals, and the final check to a person.
What the Article Covers
A table splitting the work between Claude and the person, and a one-year schedule from the business start date to the tax return.
How to catch missing entries by matching the books against card and bank statements, even without a separate business account.
Why an employee's side-business loss is first deducted from salary, so a loss that can be carried forward three years often never remains, according to the law.
This article was researched and written with AI, so errors may remain. I am filing this way myself this year, and if it works, I will publish the script and prompts.
The division-of-work table, the one-year schedule, sample journal entries, and the tax rules are all in the full article on note (in Japanese).
Read the rest on note, in Japanese →StratAIX apps are still available on the App Store.