China Sourcing Trade Documents Guide — PI, CI, PL, B/L, C/O and Why Each One Matters
The goods can sail, but if the paperwork is off, they stop at the port

Hello, this is GreenFrog Seoul.

"The goods were clearly loaded, but customs held them for days saying the invoice amount didn't match."
"The packing list and the actual box count were different, so the inspection failed."
"I skipped the certificate of origin and ended up paying the full duty I could have cut."

In China sourcing, trouble doesn't only come from the goods. More often, a well-made product gets stuck at the port over a single sheet of paper. The container crosses the ocean, but if the documents don't line up and customs won't release them, the goods just rack up storage fees in a bonded warehouse. In trade, documents aren't an appendix that follows the goods — they're the key that makes the goods move.

Trade documents aren't a fussy administrative chore — they're a bundle of promises proving "what this product is, how much it costs, where it came from, and whose it is." The moment that bundle contradicts itself, customs stops the goods cold.

Today we cover the five core documents a Korean seller meets almost every time they import from China — PI, CI, PL, B/L, and C/O. What each one does, where things tend to go wrong, and what to cross-check when you receive them, distilled to the practical essentials. Skim it before your next shipment, and you can head off the kind of accident that strands goods at the port.

1. Why Trade Documents Matter — How Paper Locks Up Goods

A domestic deal ends with the goods and a tax invoice or so. But the moment you cross a border, the story changes. Customs doesn't open the container in front of them and count every item. Instead, they read the documents and judge the goods. So when what's written on the documents and the actual goods don't match, customs treats that gap as a "problem" and stops the clearance.

The key here is that the documents have to agree with each other too. The amount on the invoice, the quantity on the packing list, and the cargo details on the bill of lading all have to align as one body. If even one number is off — a different box count, a different product name, a different amount — customs grows suspicious, and suspicion turns straight into delays and extra cost.

2. The Five Core Documents — PI, CI, PL, B/L, C/O at a Glance

There are many kinds of trade documents, but the ones a Korean seller actually handles every time in China sourcing are usually five. They're easy to remember in the order a deal unfolds: the PI when you order, the CI and PL when goods ship out, the B/L once they're loaded, and the C/O when you want to cut duties.

The five do different jobs, but in the end they're different faces of one deal. What the PI promises gets realized in the CI and PL, the title passes through the B/L, and duties get settled with the C/O. So you shouldn't look at these documents in isolation — you have to bundle them and check whether they all point to the same deal.

3. PI — The Document That Pins Down the Start of a Deal

The PI (Proforma Invoice) is the starting point of a deal. Once you've agreed price, quantity, specs, lead time, payment terms, and Incoterms with the factory, the factory issues a PI that puts that agreement on one sheet. Its form is an invoice, but in practice it acts as an order confirmation and a condensed contract. A seller typically wires the deposit on the basis of this PI.

What a PI must include

• Product, specs, quantity — what, how many, to what standard
• Unit price and total — with the currency (USD/CNY) made clear
• Incoterms — the term and place, like "FOB Shenzhen" (see Ep.39)
• Payment terms — deposit ratio, balance timing (e.g. T/T 30:70)
• Lead time — how many days after payment until shipment
• Factory account details — the exact SWIFT code and account to receive payment

The more thorough the PI, the fewer the headaches later. Nail down the unit price, specs, and lead time here, and when the goods later differ from the promise, you can point to "this is what the PI says." Take a sloppy PI with a lot agreed only verbally, and you'll have no paper to lean on when a dispute breaks out (see Ep.36).

4. CI and PL — The Pair That Gets You Through Customs

When the goods are finished and shipping out, the factory issues the CI and PL. These two move almost as a pair and are the core documents of import clearance. Customs looks at these two sheets to assess duties and verify the goods.

CI (Commercial Invoice) — "how much is this deal worth"

The CI (Commercial Invoice) proves the actual transaction amount. If the PI is "the promise at order time," the CI is the firm proof of "this is what I shipped and this is the amount." Customs calculates duties and VAT based on the amount on this CI. So the CI amount becomes the reference point for taxes.

PL (Packing List) — "how it's packed"

The PL (Packing List) records how the cargo is divided and packed across boxes. It includes box count, quantity per box, net and gross weight, box dimensions, and so on. When customs opens a container to inspect, they cross-check this PL against the actual cargo, and the forwarder uses this information to plan loading and transport (see Ep.35).

5. B/L — The Goods' "Title Ticket"

The B/L (Bill of Lading) is special among the five. It's not a mere information document but a certificate carrying the very right to claim the goods. The carrier issues it when loading the cargo onto the ship, and whoever holds this paper claims the goods at the destination port. That's why the B/L is called the goods' "title ticket."

The three jobs a B/L does

There are broadly two kinds of B/L: the OBL (Original B/L), where originals must be exchanged to claim the goods, and the Surrender B/L (or telex release), delivered electronically without originals. In a deal where payment is done and trust is built, a surrender handles it quickly; but in a deal where the balance and the handover are swapped, the original B/L acts as a safeguard.

6. C/O — The Paper That Cuts Your Duties

The C/O (Certificate of Origin) officially proves "in which country these goods were made." For Chinese goods, a designated body in China (the CCPIT — China Council for the Promotion of International Trade, etc.) issues it. Unlike the other documents, it isn't always required for clearance, but it plays a decisive role when you want to cut duties.

Korea and China have an FTA, so if you have a Korea–China FTA-form certificate of origin (Form), you can reduce or even waive duties depending on the item. Bring in the very same goods, and this one sheet changes the duty rate based on whether you have it. So for an FTA-eligible item, the C/O isn't optional — it's a must-have document to secure (see Ep.24).

7. Common Document Mistakes

Knowing each document's role isn't the end. In practice, a small slip snowballs into a multi-day clearance delay. Here are the document accidents Korean sellers run into again and again dealing with Chinese factories.

What to secure before shipment

• The draft of every document — get them before shipout and cross-check
• Matching product name, quantity, amount, weight — line up the CI, PL, and B/L line by line
• Incoterms and currency — confirm the PI and CI carry the same terms
• The required-document list — check item-specific extras like certificates and inspection reports (see Ep.10)

8. GreenFrog Seoul's Trade Document Support

Once you know the types, you can secure trade documents yourself. But cross-checking whether the factory's documents agree with each other, preparing every extra document clearance needs, and not missing tax-saving levers like the FTA — these need trade experience behind them. That's the part GreenFrog Seoul handles with you, or for you.

Support services

What changes when we work together

• Clearance that doesn't stall — documents matched in advance so goods aren't held at the port
• Safe payment — fake PIs and account fraud filtered out beforehand
• Lower duties — legal savings through the C/O and the FTA
• Less burden — complex document work handled with local experience

9. Trade Document Checklist

Items to check, stage by stage, ahead of your next shipment.

Order stage (PI)

• Product, specs, quantity, unit price, and total are clearly stated on the PI
• Incoterms and currency are specified
• The factory account was verified by a separate channel before wiring
• Payment terms and lead time are pinned down in writing

Ship-out stage (CI, PL)

• The CI amount matches the actual transaction value (no undervalue)
• The PL box count, quantity, and weight match reality
• The numbers on the CI, PL, and B/L agree with each other
• The product name is stated precisely (down to material and use)

Loading / clearance stage (B/L, C/O)

• The timing of balance payment and B/L handover is agreed
• The B/L type (original / surrender) is set to match the deal's trust level
• For an FTA-eligible item, the C/O was issued before clearance
• Item-specific extra certificates and inspection documents are all secured

Wrapping Up — Mind the Documents as Much as the Goods

Compress today's five documents to one line each:

• PI: the order confirmation that pins down the start. Always verify the account separately
• CI: the proof of the real amount and the basis for duties. No undervalue
• PL: the breakdown of how it's packed. Box count, quantity, weight, exact
• B/L: the title document to claim the goods. Lock the balance and handover together
• C/O: the origin proof that cuts duties. Secure it before clearance

The core of trade documents comes down to one thing: no matter how good the goods are, if the documents are off they stop at the port. And that mismatch usually starts not with some grand accident but with one digit in a box count, one line of an amount, one forgotten sheet of paper. If a shipment is ahead, don't just mind the goods — pull the document drafts and cross-check them line by line. Those few minutes spent confirming that all five documents point to the same deal will save you a multi-day clearance delay and needless cost. GreenFrog Seoul works alongside Korean sellers — from document review to PI checks, C/O and FTA savings, and clearance document support — so your goods don't stop at the port. If the documents feel complex and you're not sure where to start, reach out anytime.