A few months after filing my second 確定申告 as a sole proprietor running guesthouses in Tokyo, I got an email from my tax accountant with a subject line that made my stomach drop: “About a possible 税務調査.” It turned out to be nothing — just routine administrative guidance (行政指導), not a formal tax audit — but it sent me down a rabbit hole of figuring out what a real tax audit actually involves, and what I’d need to have ready if one ever showed up.

TL;DR

  • A 税務調査 (zeimu chosa) is a review of your filed returns against your actual records. On-site audits are generally subject to advance notice, though the NTA can proceed without notice in specified cases.
  • The NTA says it collects and analyzes materials from multiple angles and uses risk-based methods including AI, with active attention to internet/sharing-economy activity and non-filers — it doesn’t publish exact selection criteria.
  • Auditors mainly want receipts, bank statements, and OTA payout records that reconcile with what you declared; inconsistent revenue or a gap between reported revenue and deposits is a practical thing to check, not a confirmed trigger.
  • Blue return (青色申告) filers generally keep books and financial statements for 7 years, though some documents are 5-year items; electronic transaction data you receive digitally must be retained under the e-bookkeeping law (電子帳簿保存法), with search rules that have exceptions.
  • Good habits before an audit — not scrambling during one — are what actually keep the process short.

Who Actually Gets Selected for a Tax Audit?

Most small operators who face a 税務調査 aren’t chosen because they did anything wrong. The National Tax Agency says it collects and analyzes materials from multiple angles, uses risk-based methods including AI, and actively examines internet/sharing-economy activity and cases where no return has been filed — cross-referencing this against data it already holds, such as bank interest reports and prior-year filings. Where applicable, minpaku-system registration and periodic reporting data, such as lodging days and guest counts, may also be available to relevant authorities including the NTA. The agency doesn’t publish exact selection criteria, so treat the following as practical things to reconcile rather than confirmed triggers: revenue that looks inconsistent year over year, a mismatch between your listing/booking activity and reported revenue, an expense spike without a matching revenue increase, or gaps in your filing history. Whether new registration as an invoice-issuing business (適格請求書発行事業者) itself draws extra attention isn’t something the NTA has published either — worth being aware of, but not something to treat as confirmed.

What Records Will an Auditor Actually Ask to See?

An auditor will ask for the same records that support your kakutei shinkoku filing: receipts, invoices, bank statements, and a ledger that ties them together. This is where the gap between “what I filed” and “what I can actually prove” bites people. Under regular taxation, claiming the full consumption-tax input credit generally requires retaining your books plus a qualified invoice or simplified qualified invoice showing the issuer’s registration number. There are exceptions — certain book-only cases like public transport and vending-machine purchases, a small-purchase transitional measure, and a transitional credit for purchases from non-registered suppliers (80% through September 30, 2026, and 50% from October 1, 2026 through September 30, 2029) — so a missing registration number isn’t automatically disqualifying, but it’s still the detail auditors check first. Separately, under the Electronic Books Preservation Act (電子帳簿保存法), invoices, receipts, and OTA statements you receive as data — email invoices, PDF receipts — can be printed out, but the electronic transaction data itself must still be retained, generally searchable by date, amount, and counterparty. That search requirement has exceptions too: since 2024 the NTA has waived it for taxpayers whose sales in the second prior fiscal year were JPY 50 million or less, and there’s a hardship measure for taxpayers who can respond to download and printout requests instead. Paper receipts can just stay on paper — nothing requires digitizing them. If you do want scans to replace the paper originals, that falls under the separate scanner-preservation regime, which requires timely input, image and readability standards, search and ledger-linking, and anti-tampering controls such as a compliant timestamp or an equivalent correction/deletion-history system; NTA guidance describes the maximum ordinary processing cycle for important documents as about two months plus roughly seven business days, and if you miss that window you’re expected to keep the paper original rather than rely on a late scan. Blue return (青色申告) filers generally keep books such as journals and general ledgers, financial statements, and cash/deposit transaction documents like receipts and passbooks for 7 years. Other transaction documents — invoices, estimates, contracts, delivery slips, shipping documents — are generally only 5 years, and cash/deposit documents can drop to 5 years if your business and real-estate income two years prior was JPY 3 million or less. Consumption-tax invoices kept for input-credit purposes are generally 7 years regardless — a longer and more granular set of rules than most people intuitively plan for, so when in doubt, keep it, and check with your accountant on which bucket a given document falls into.

How Should Guesthouse Operators Prepare Differently From Other Freelancers?

Guesthouse and short-term rental operators have a reconciliation problem most freelancers don’t: revenue arrives from multiple OTAs on different payout schedules, net of commission already deducted. An auditor doesn’t just want to see your bank deposits — they want the gross booking amount, the OTA commission taken out, and the net deposit, tying back to each individual reservation. Recording only the net deposit as “revenue” understates both revenue and expenses in a way that looks sloppy even when the tax owed comes out the same. The fix is boring but effective: reconcile at the reservation level, not the bank-statement level, and keep the OTA payout report alongside the receipt for anything paid out of that revenue (cleaning, linen, contractor work). Tools like Reshito can help with the receipt side of this — keeping fields like date, payee, amount, and tax rate searchable across mixed paper and digital receipts — but they’re not a substitute for confirming your legal storage requirements with your accountant.

What Happens During and After the Audit?

On-site tax audits are generally subject to advance notice in principle — usually by phone — with a request for a specific date range of records, though the NTA can proceed without advance notice in specified cases. You — or your tax accountant, if you use one, which is strongly recommended for this — sit down with the auditor, walk through the records for the period in question, and answer questions about discrepancies as they come up. If everything reconciles, it typically ends there. If it doesn’t, you may owe back taxes plus interest, and in cases of clear underreporting, a penalty tax (加算税) on top. How quickly you can produce a specific document when asked is a major factor in how long this takes — an audit where every receipt is legible, timestamped, and indexed by reservation moves fast; one where you’re digging through a shoebox does not.

FAQ

Q: How likely is a small operator to actually be audited?

Full on-site audits of very small operators are relatively rare, but simplified contact (簡易な接触) — such as an お尋ね letter asking you to clarify a specific number — is much more common. This is treated as administrative guidance (行政指導), not a tax audit, but it can still escalate into a full audit if your response doesn’t resolve the question.

Q: Do I need a tax accountant (税理士) to handle an audit?

It’s not legally required, but for anyone earning multi-source income like OTA payouts plus ancillary revenue, having a 税理士 represent you during the audit is standard practice and generally worth the cost relative to the risk of mishandling a question.

Q: What’s one practical step I can take to prepare before I’m ever audited?

Reconcile your records monthly instead of once a year — matching each OTA payout to the underlying reservations and keeping receipts indexed as you go means there’s less to reconstruct if a request ever comes.

This post is for informational purposes only and does not constitute legal or tax advice. Please consult a qualified professional for your specific situation.