Most foreign companies that get flagged by Japan Customs (税関) did not do anything dramatic. They repeated a small procedural inconsistency across several shipments until a pattern formed, and the pattern is what triggers scrutiny. If your company imports into Japan without a Japan entity, using either an Importer of Record structure or a customs procedural agent, the risk is rarely a single bad decision. It is an accumulation of small mismatches that a post-clearance audit (事後調査) is specifically designed to surface. This post walks through the mistakes we see most often, why each one matters, and what to check before your first shipment, plus how to correct course if one of these has already happened.
Mistake One: Treating IOR and ACP as Interchangeable
This is the most consequential mistake because it happens at the structuring stage, before any goods move.
Importer of Record (IOR) is a structure where a Japan-resident provider becomes the legal importer. The provider purchases the goods from the overseas seller, files the import declaration (輸入申告) in its own name, and re-sells to the Japan-based buyer. The provider carries importer liability and issues a Qualified Invoice (適格請求書) so the downstream buyer can claim consumption tax input credit.
Attorney for Customs Procedures (ACP, 税関事務管理人) is structurally different. Your company remains the legal importer named on the declaration. A Japan-resident agent acts as your procedural agent before Japan Customs under the Customs Act (関税法). This service is available only when your company is a non-resident with no Japan address, office, or place of business. Consumption tax recovery under ACP runs through a separately appointed tax administrator, not through the agent relationship itself.
These are not two flavors of the same service. The question "do we have a Japan entity" is not even the right sorting question; a company with a Japan entity generally needs neither structure. The right question is who is legally and commercially the importer, and who bears title and risk. Providers who present IOR and ACP as interchangeable options, or as a menu you pick from based on convenience, are signaling that they have not thought through which structure your transaction actually requires. Choosing the wrong one, or drifting between them shipment to shipment without documentation, is itself an audit flag: Japan Customs looks for consistency in who is named as importer and why.
Mistake Two: Inconsistent Product Descriptions or Tariff Classification
A single shipment with a slightly generic product description rarely draws attention. The same product described three different ways across five shipments does. Customs officers reviewing entries, and post-clearance auditors reviewing history, compare declarations against each other, not just against the tariff schedule in isolation. Divergent descriptions or shifting tariff classification for what is functionally the same item reads as either carelessness in your compliance process or an attempt to manage duty exposure shipment by shipment. Neither is a good look, and both increase the odds of a deeper file review.
The fix is not complicated: fix the classification once, document the reasoning, and reuse it. If the product genuinely changes (a new revision, a different bill of materials), document why the classification changed rather than letting it drift silently.
Mistake Three: Undervaluing or Inconsistently Valuing Goods
Valuation problems tend to show up in two forms. The first is a value that looks low relative to comparable goods, inviting a valuation challenge. The second, more common in related-party or repeat-shipment scenarios, is a value that moves around without an obvious commercial explanation, such as a distributor discount schedule or a currency adjustment. Customs valuation is expected to reflect the actual transaction price paid. When related entities are involved, the underlying pricing logic should be consistent and defensible on its own terms, not adjusted shipment to shipment to manage duty outcomes.
If your company transacts with an affiliate or repeat counterparty, keep a simple internal record of why the declared value is what it is for each shipment. That record is what turns a valuation question during an audit into a five-minute clarification instead of an extended inquiry.
Mistake Four: Ignoring What Incoterms Actually Determine
Incoterms are often treated as a shipping-logistics detail buried in a purchase order. In an IOR or ACP structure, they determine something more consequential: who functionally controls the goods at the point customs treats as import, and whether that matches who is structurally supposed to be the importer. A mismatch between the commercial terms of sale and the declared importer creates exactly the kind of substance-over-form question a post-clearance audit is built to catch. Before your first shipment, confirm that the Incoterm chosen is consistent with the structure you are using, IOR or ACP, and not left to whatever term the overseas seller's standard contract happens to use.
Mistake Five: Skipping Denied-Party and Sanctions Screening
Some companies treat sanctions and denied-party screening as something that only matters for controlled or dual-use-adjacent goods. It should be run before the first shipment regardless of product category, covering the overseas seller, the Japan buyer, and any intermediary named in the transaction chain. Screening once at onboarding and never again is also a gap; counterparties and ownership structures change, and a screening result from a year ago is not a current one.
Mistake Six: Not Confirming Qualified Invoice Issuer Status
If your Japan buyer needs to claim consumption tax input credit on the resale, the entity issuing that invoice must be a registered Qualified Invoice Issuer (適格請求書発行事業者). This matters specifically in the IOR structure, since the reselling importer is the one issuing that invoice. Confirm this registration status directly rather than assuming any provider quoting IOR services has it in place; an unregistered issuer breaks the buyer's input credit chain, which becomes the buyer's problem at tax filing time, not yours, but it will come back to you as a relationship problem.
Mistake Seven: Assuming One Setup Covers Every Future Product Line
An IOR or ACP arrangement approved and screened for one product category does not automatically extend to a new one added later. This is especially true if the new line moves toward an export-control-adjacent product category, dangerous goods, or any other regulated classification different from what was originally screened. Each meaningfully different product category warrants its own re-screening pass. Treating the original setup as a blanket clearance is one of the more common ways a company that has been importing cleanly for years suddenly triggers a review after adding a new SKU.
Checklist Before Your First Shipment
Before committing to a structure or a first shipment, confirm the following: (a) the structure chosen, IOR or ACP, matches who is legally the importer and who bears commercial risk, not just whichever is more convenient to set up; (b) product descriptions and tariff classification are fixed and documented, with a rationale you can produce on request; (c) valuation methodology is consistent and defensible, particularly for related-party or repeat transactions; (d) the Incoterm in the sale contract matches the structural intent of who is functioning as importer; (e) denied-party and sanctions screening has been run on all parties in the chain, and a cadence exists for re-screening; (f) if the structure is IOR, the entity issuing the resale invoice is a confirmed Qualified Invoice Issuer; (g) any new product category added later, especially anything dangerous-goods or export-control-adjacent, is re-screened rather than assumed covered.
If a Mistake Has Already Happened
If your company has already received a post-clearance audit inquiry, or suspects an inconsistency in past filings, the calm and correct response is the same: gather the actual shipment history (declarations, invoices, correspondence) before responding to any inquiry, identify where descriptions, valuations, or structural roles diverged, and correct the pattern going forward rather than trying to explain away each entry individually. A post-clearance audit finding is not automatically a penalty; it is a request for consistency and documentation, and a company that responds with organized records and a corrected go-forward process is in a materially different position than one that responds piecemeal. If the inquiry touches valuation, classification, or the underlying structure itself, get that reviewed before you reply rather than after.
None of these mistakes require a large operation to happen. A single-shipment importer and a multi-shipment distributor are both exposed to the same patterns; the multi-shipment case simply generates the paper trail faster.
This article is informational only and does not constitute legal, tax, or regulatory advice. Consult a qualified advisor before acting on the content. Last updated: July 2026.