Why do duties differ on the very same goods?
Korea-China FTA Preferential Tariff Guide: From Certificate of Origin (C/O) to Retroactive Claims and Origin Verification

Hello, this is Green Frog Seoul.

“It was made in a Chinese factory, so the Korea-China FTA duty is 0%, right?”
“Doesn’t the factory just take care of the certificate of origin?”
“I forgot to claim the preferential tariff at import declaration. Can I no longer get the duty back?”
“Months later, Customs suddenly asked for origin documents. Did something go wrong?”

Our last article covered customs value, the basis for calculating duty. Multiply the customs value by the rate and you get the duty. But there is a way to lower that rate itself: the Korea-China FTA preferential tariff. For the same goods at the same customs value, a single certificate of origin can change the duty you actually pay from, say, 8% to 0%.

Many people assume “made in China means the Korea-China FTA applies.” But the preferential tariff is not granted automatically just because the goods were made in China. You must confirm that the product is on the staging schedule, that it satisfies the Korea-China FTA rules of origin, that you hold a properly completed certificate of origin in the prescribed form, and that the goods were shipped directly without passing through a third country such as Hong Kong.

The preferential tariff is not a “discount for coming from China.” It is a conditional preferential rate that applies only when you meet the rules of origin and can prove that with evidence. Miss the conditions or fail to prove them, and you will pay the duty back later.

This guide covers the basic structure of the preferential tariff; how to check whether your product qualifies; the three pillars of the rules of origin; the difference between “manufactured in” and “originating in”; issuing the certificate of origin (C/O); the direct-transport rule; preferential claims and retroactive refunds; responding to origin verification; de minimis thresholds and validity; and recordkeeping.

1. What the preferential tariff really is: a card that lowers the rate itself

Import duty is generally calculated using one of three rates: the base rate, which applies with no conditions; a flexible or provisional rate that takes priority in specific situations; and the FTA preferential rate for goods originating in an FTA partner. The Korea-China FTA entered into force on December 20, 2015, and is designed to eliminate tariffs in stages, from immediately on entry into force up to 20 years, depending on the product.

The mechanics are simple. Duty equals customs value × rate, and the FTA replaces that rate with a preferential rate lower than the base rate. For example, on a product with an 8% base rate and a customs value of KRW 50,000,000, the base-rate duty is KRW 4,000,000. If the same goods qualify for a Korea-China FTA preferential rate of 0% and meet the requirements, the duty is zero. That is millions of won turning on a single clearance.

2. First, is your product covered: check the HS code and staging category

A preferential-tariff review always starts from the HS code. Only once the 10-digit tariff line is fixed can you compare that product’s base rate with its Korea-China FTA preferential rate, and the rules of origin are also set by HS code. Get the HS code wrong and both the rate and the origin test go wrong with it.

In practice, this order avoids confusion:

1. Fix the exact 10-digit HS code of the imported goods.
2. Confirm the product’s base rate (or WTO rate, etc.).
3. Check this year’s preferential rate for the same product on the Korea-China FTA staging schedule.
4. Determine whether the preferential rate is lower than the base rate, and if so, by how much.
5. If there is a real saving, move on to the rules of origin and evidence.

You can compare rates by HS code on the Korea Customs Service FTA portal or the clearance system. Staging categories are usually shown as “immediate elimination,” “equal elimination over N years,” “partial reduction,” or “excluded,” and many products step down one level each year as of January 1.

3. Rules of origin: judging “where it came from” by rule

The heart of the preferential tariff is determining whether the product originates in China (the other party). The Korea-China FTA recognizes origin in two broad ways: goods wholly obtained or produced in that country, and goods that, even with materials from several countries, satisfy the product-specific rule of origin (PSR). The manufactured goods most of us handle fall into the latter category.

Product-specific rules are usually set by one (or a combination) of the following methods:

The change-in-classification rule is further divided into a 2-digit change (CC), a 4-digit change (CTH), and a 6-digit change (CTSH). The larger the required change, the more substantial the processing demanded. Regional value content can be calculated by a build-down method that subtracts the value of non-originating materials from the finished-product price, or a build-up method that adds originating materials, processing costs, and the like; the required percentage varies by product.

4. “Made in China” and “originating in China” are not the same

This is the most common misunderstanding. Passing through a Chinese factory does not automatically make the origin China. The Korea-China FTA separately lists minimal operations (simple processing) that cannot confer origin. No matter that the work was done in China, if it amounts only to a simple operation, origin is not conferred.

Origin may not be recognized where the goods underwent only operations such as:

• packing, repacking, or affixing labels and marks for transport or storage;
• simple cutting, sorting, washing, painting, or assembly that does not change the essential character;
• merely combining items into a set; or
• simple dilution with water or the like that does not change the nature of the product.

For example, if nearly finished goods are brought in from a third country and, in China, only labeled and boxed for export, the actual origin may not be China. Obtaining and using a Korea-China FTA certificate of origin for such goods leads to origin being denied on verification and duties being collected retroactively.

A cushion when you just miss the rule: de minimis

There is a buffer for cases that just barely fail the change-in-classification rule. Under the de minimis rule, even if some non-originating material did not undergo the required change, origin can still be recognized if the value of that material is at or below a set share of the finished-product price (generally around 10% for typical manufactured goods). Note that some products, such as textiles and apparel, use a weight-based threshold and other exceptions, so check by product.

A device that combines materials: cumulation

If your structure sends Korean materials to a Chinese factory to make the finished goods, consider cumulation. Where originating materials from the other party (Korea) are used in production in China, this rule treats them like Chinese originating materials, which helps in the origin determination. For transactions involving free-issue materials or designated material supply, it is worth reviewing whether cumulation applies.

5. The certificate of origin (C/O): who issues it, where, and how

Once the rules of origin are met, the document that proves it is the certificate of origin (C/O). The Korea-China FTA uses an authority-issued system: rather than the exporter or producer self-certifying, an authorized body issues the certificate after review.

For a Korean importer bringing goods in from China, the Chinese exporter must obtain a Korea-China FTA certificate of origin from a local issuing body and send you the original. That is why, in practice, it is important to agree clearly at the ordering and contract stage that the “original Korea-China FTA certificate of origin” will be provided.

Items you must reconcile on the certificate of origin

The certificate must line up with the invoice, packing list, and bill of lading. Mismatched items can result in denial of the preferential tariff.

• Do the exporter, producer, and importer details match the actual parties to the transaction?
• Are the product description and HS code (6 digits) consistent with the invoice and the Korea-side tariff line?
• Does the stated rule of origin match the rule for that product?
• Do the quantity, weight, invoice number, and amount match the actual documents?
• Are the issue date, signature, and seal valid (validity is one year from the issue date)?

6. The direct-transport rule: the trap of routing through Hong Kong or a third country

Even a flawless certificate of origin can be blocked by the transport route. The Korea-China FTA in principle requires that goods be transported directly from China to Korea. If originating goods are mixed with other goods or further processed while passing through a third country, the identity of the origin is considered compromised.

That said, transiting a third country is not automatically prohibited. Even if goods are unavoidably transshipped through Hong Kong, Singapore, or elsewhere for logistical reasons, they can still qualify as directly transported if you prove that only operations necessary for transport, such as unloading, reloading, and storage, were performed there without further processing, and that the goods remained under customs control. This calls for documents such as a non-manipulation certificate issued by the transit country’s customs or a through bill of lading.

7. Preferential claims and retroactive refunds: there is a way even if you miss the claim

Once the origin requirements are met, you still have to claim the preferential tariff. Customs will not reduce the rate on its own just because you qualify. As a rule, you must claim the preferential tariff at import declaration, and no later than before the import declaration is accepted, while holding the certificate of origin.

In practice, though, the certificate of origin is sometimes delayed or a staffer misses the claim, and the goods clear at the base rate. There is a remedy here too: a retroactive preferential claim (application for correction). Even if you did not claim the preferential tariff before acceptance, you can obtain it and recover the overpaid duty by claiming, with the certificate of origin, within one year of the date the import declaration was accepted.

8. Origin verification: clearance is not the finish line

Do not relax just because the goods cleared under the preferential tariff. Customs can verify origin even after clearance. The Korea-China FTA in principle uses indirect verification, in which the importing country’s customs asks the exporting country’s issuing body or customs to confirm, though additional documents may also be requested.

If the basis for origin is not confirmed on verification, or there is no response, the preferential tariff is denied. The consequences follow:

• the preferential rate already applied is canceled and the difference from the base rate is collected;
• penalties and additional charges may be imposed on top of the collected duty; and
• verification can extend to other import entries for the same supplier and product.

So do not stop at simply holding a certificate of origin; secure the materials that support it. A bill of materials, evidence for originating materials, a description of the manufacturing process, and a cost breakdown, materials that let you reproduce the origin determination, are central to a verification response.

9. De minimis, validity, and common mistakes

Here are the detailed rules and mistakes that come up repeatedly in practice.

Mistakes that come up often on the ground

• Spending time preparing documents when the preferential rate is not actually lower than the base rate.
• Accepting the 6 digits the factory wrote arbitrarily, without fixing the Korea-side HS code.
• Securing a certificate of origin for form’s sake without reviewing whether the rules of origin are met.
• Failing to prepare non-manipulation evidence for transactions transiting Hong Kong or a third country.
• Missing the one-year retroactive deadline and giving up a refundable duty.
• Not securing material and cost data for verification, which leads to retroactive collection.

10. Managing evidence: not a single certificate, but one file

The preferential tariff starts with a single certificate of origin, but to withstand verification you should manage it at the level of a file. Bundling the following materials by import declaration number means a verification request will not catch you off guard.

11. Korea-China FTA preferential-tariff practical checklist

Before placing an order or signing a contract

• Fixed the Korea-side HS code (10 digits) of the imported goods.
• Compared the base rate with this year’s Korea-China FTA preferential rate to confirm a real saving.
• Checked the product’s rule of origin (change in classification, value content, or specific process).
• Stated in the contract the obligation to provide the original certificate of origin and cooperate with verification.

During production and origin determination

• Reviewed, via the bill of materials, whether non-originating materials meet the rule of origin.
• Confirmed the goods did not undergo only simple (non-qualifying) operations.
• Reviewed the possibility of applying de minimis or cumulation.
• Secured material and cost data that can reproduce the origin determination.

Before shipment and clearance

• Reconciled the draft certificate of origin against the invoice and packing list.
• Confirmed that the description, HS code, quantity, amount, and issue date all match.
• Prepared direct-transport evidence (non-manipulation certificate, etc.) if a third country is transited.
• Scheduled the preferential claim before the import declaration is accepted.

After clearance

• If the preferential tariff was missed, considered a retroactive claim within one year.
• Established a system to keep origin materials by declaration number for five years.
• Confirmed where the determination materials are held, in case of a verification request.
• For recurring imports, standardized an origin-materials management procedure with the supplier.

Conclusion: a certificate of origin is not paperwork, but risk management

The Korea-China FTA preferential tariff is the surest duty-saving card available to businesses importing from China. But approaching it with “it’s Chinese, so of course it’s 0%” can turn a saving into retroactive collection and penalties months later. The preferential tariff is a conditional benefit that survives only when you meet the rules of origin and prove it with evidence.

The order is clear: first confirm a real saving by HS code, then determine whether the rules of origin are met using the actual materials and process, hold an accurate certificate of origin, prove direct transport, claim on time, and keep the materials for verification. These six steps must interlock for the preferential tariff to survive beyond the moment of clearance and through verification.

There is no need to delay clearance just because you lack the certificate of origin now. Protect the schedule first, then recover the duty within a year through a retroactive claim. Conversely, forcing a preferential claim where origin is uncertain is risky. When in doubt, it is safer to confirm the origin determination with a customs broker first.

Green Frog Seoul helps Korean importers organize origin materials into a form that is easier to review with a customs broker, including requesting the original Korea-China FTA certificate of origin and determination materials (bill of materials, cost breakdown, etc.) from Chinese suppliers, reconciling HS codes and rules of origin, and securing direct-transport evidence. Confirm the final rate application and declaration method with a customs professional based on the actual transaction documents.