Question 1

Do I need to file the 開業届? What if I don't?

Accepted Answer

The 開業届 registers your individual business, filed at the 税務署 within 1 month of starting. There's no fine for being late, but without it you can't use the blue return (青色申告, big tax savings) and it's harder to prove you're self-employed (visa, loans, daycare).

Easy Kojin prepares the document for you — see the 'Open Kojin' menu.

Question 2

Blue return (青色) or white return (白色)?

Accepted Answer

White is simpler but has no benefits. Blue lets you deduct up to ¥650,000 from profit (often ¥100,000+ less tax per year), carry losses forward 3 years, and pay salaries to family.

To use blue, file the 青色申告承認申請書 by March 15 (or within 2 months of opening). We recommend blue for almost everyone.

Question 3

What can I claim as expenses (経費)?

Accepted Answer

Anything needed to earn your income: work fuel and tolls, materials, tools, phone/internet (business share), workspace rent, advertising, app fees, safety gear, professional courses.

NOT allowed: personal spending, everyday clothes, family groceries, fines. When in doubt, ask the app's AI Assistant.

Question 4

I work from home — can I deduct rent and utilities?

Accepted Answer

Yes, the business PORTION (家事按分). If your work room is 20% of the home, you can claim ~20% of rent and utilities. Keep a note of your reasoning (area or hours).

OWN home: there's no 'rent to yourself', but you can prorate utilities/internet and depreciate the business share of the building (register under Assets). The app's transaction form has a built-in proration calculator.

Question 5

I bought an expensive car/computer — is it an expense?

Accepted Answer

Depends on the amount: under ¥100,000 is a normal expense. ¥100,000–¥199,999 can be split over 3 years (一括償却). On blue return, up to ¥300,000 can be fully expensed in the year (少額特例). Above that, depreciate over the legal useful life — new car 6 years, computer 4 years.

The app's 'Assets' screen computes all of this automatically.

Question 6

When do I file and pay (確定申告)?

Accepted Answer

You file for January–December between February 16 and March 15 of the next year, paying income tax then. Resident tax and health insurance bills arrive later through the year.

Tip: don't leave it to March — with the app tracking everything year-round, filing becomes just a review.

Question 7

Do I need to keep receipts? For how long?

Accepted Answer

Yes! Keep receipts and proofs for 7 years (blue) or 5 years (white). The tax office may ask during an audit.

Photographing them in the app keeps things organized and searchable, but also keep the paper originals in a box per year.

Question 8

What is the インボイス (invoice) system? Should I register?

Accepted Answer

It's the qualified invoice system for consumption tax. You only NEED to register if your clients are businesses that require invoices. If you sell to consumers (delivery, salon, direct work), you usually DON'T.

Careful: registering means you start paying consumption tax. Talk to an accountant first — the app has a referral in the 'Tax accountant' menu.

Question 9

Do 国民健康保険 and 国民年金 reduce my tax?

Accepted Answer

Yes — 100% of what you paid in the year is deductible (社会保険料控除) and lowers your tax. Keep the payment proofs.

In the app, enter the total under Settings → 'Social insurance paid' and the tax estimate includes it.

Question 10

I earned little (or had a loss) — should I still file?

Accepted Answer

If profit is below your deductions, income tax may be zero and filing may not be mandatory — BUT it's usually worth it: it proves your income (visa, apartment, loans), lowers your health insurance, and on blue return the loss offsets profits for the next 3 years.

Question 11

Can I use the same bank account for everything?

Accepted Answer

You can, but it's not recommended. Mixing personal and business money makes expenses hard to track and increases filing mistakes.

Ideal: one account (and one card) just for the business. Reconciling with the app becomes easy.

Question 12

Roughly how much tax will I pay?

Accepted Answer

Rule of thumb for profit (revenue − expenses) up to ~¥4M: set aside 15–25% for income tax + resident tax + health insurance + business tax combined. The app's dashboard shows a real-time estimate as you record — no year-end surprises.

Kojin FAQ

Still have questions?