Prepare for Paper 2 by treating every problem as a decision chain rather than studying topics in isolation. Classification problems get the GRI order, valuation problems get the method hierarchy, and origin problems get the preferential/non-preferential distinction. Use a two-line written justification per problem, an adjustment-tracing drill over past-style problems, and the five readiness checks at the end to gauge progress.
Why classification starts with the GRI order, not the product name
HS classification follows an explicit hierarchy, the General Rules for the Interpretation of the Harmonized System. Apply GRI 1 first; move to GRI 3(a), then 3(b), then 3(c) only when two or more headings each appear to cover the goods.
Start every classification drill by applying GRI 1. Describe the goods, note which heading text includes or excludes them, and stop at the first heading whose terms are conclusive. GRI 3 only becomes relevant when two or more headings each seem to cover part or all of the description. Its order is fixed: 3(a) asks which description is more specific, 3(b) asks which component or material gives the composite good its essential character, and 3(c) falls back to the heading that occurs last in the nomenclature.
The order matters because skipping steps loses your reference point. Before arguing essential character under 3(b), you must resolve 3(a): does each candidate heading describe the whole good, or only a component? If a heading's text fully covers the good, 3 is never reached at all. Build the habit with a two-line written justification for every problem, for example: 'GRI 1: within the terms of heading XX; GRI 3 not required.' Writing the reason fixes the sequence until applying it in order becomes automatic.
The six customs valuation methods and where each one breaks down
Valuation is a hierarchy: Method 1 is transaction value with permitted adjustments, then identical and similar goods, then deductive and computed, then fallback. The deductive-to-computed sequence can be reversed at the importer's request; each method is reached only when the earlier ones fail.
Method 1 is the starting point. Track the price paid or payable, sale-related additions such as commissions and brokerage, packing, assists, and royalties paid as a condition of sale, transport and insurance elements as your system requires, and the permitted deductions. Method 1 can be blocked by restrictions, conditional pricing, or price questions tied to a related-party relationship. Be able to explain why each blocking condition undermines the reliability of the price, because that explanation is the basis for moving on to Method 2 and beyond.
Methods 4 and 5 are easy to confuse. The deductive method starts from a unit resale price in the importing country and deducts profit, general costs, and transport or insurance elements; the computed method starts from the producer's materials and fabrication costs and adds profit and general expenses. Note the ordering nuance: in systems applying the WTO Customs Valuation Agreement, such as Korea's, the importer may request that the computed method be applied before the deductive method even when deductive data exists, so treat the 4-then-5 sequence as the default rather than an absolute rule.
| Method | Basis used | Typical trigger | Common trap |
|---|---|---|---|
| 1 Transaction value | Price actually paid or payable plus permitted adjustments | Normal arm's-length sale | Omitting assists, packing, or sale-condition royalties that belong in the base |
| 2 Identical goods | Price of goods identical in all respects | Method 1 unavailable or unusable | Ignoring differences in quantity, commercial level, or transport terms |
| 3 Similar goods | Price of commercially interchangeable goods | No identical comparables | Treating 'close but not interchangeable' goods as similar |
| 4 Deductive | Resale price minus profit, costs, and transport elements | No usable comparables; applied unless the importer requests computed first | Deducting the wrong cost items or using the wrong resale stage |
| 5 Computed | Materials, fabrication, profit, general expenses, transport | Producer cost data available, or the importer requests computed before deductive | Double-counting profit on top of already-loaded costs |
| 6 Fallback | Flexible application consistent with the scheme | Methods 1–5 exhausted | Reaching it before the earlier methods are genuinely resolved |
Tracing the tax chain from dutiable value through duty to VAT
A duty-and-tax problem is a chain: determine the dutiable value, apply the duty rate, then determine whether each subsequent tax uses a base that includes the duty. An error in the first line distorts every line after it.
Structure every computation in labeled lines. Line one: the dutiable value, stating which adjustments were included and why. Line two: the duty rate for the chosen classification code. Line three: each import-stage internal tax, noting whether its base incorporates the duty. Under the Korean system, the VAT base at import is the customs value plus duty plus other import-stage taxes, so a duty error shifts that base as well; verify the exact composition of each base in the current law and decree text you study from.
Chain drills teach you to reverse the propagation. Take one completed practice problem, change a single input — say, adding a packing-cost adjustment — and recompute, naming every line that moves and every line that does not. Then work in reverse: given a correct final answer, reconstruct which set of adjustments must have produced it. This bidirectional exercise shows how a single-line mistake appears across the whole computation, a far more useful skill than memorizing adjustment lists without seeing their downstream effect.
Preferential and non-preferential origin: two different decisions, two different rule sets
Preferential origin exists to qualify goods for FTA tariff rates and requires both the agreement's origin rules and documented proof. Non-preferential origin serves ordinary duty rates and marking purposes and follows a different test. Conflating the two produces wrong rates.
Taking the preferential path means proving three things: that the product satisfies the specific rule of origin for its classification code under that agreement, such as a change-in-tariff-classification or a value-content test; that documentary proof exists, such as a certificate of origin or an approved-exporter document; and that the shipment meets the applicable direct-transport or non-alteration conditions. If any one fails, the FTA rate cannot be claimed and the duty reverts to the basic non-preferential rate.
Practice origin problems in two steps. Step one: is a preferential claim available, and which rate does it achieve? Step two: if the claim fails — no certificate, a rule not met, transport conditions broken — which rate applies instead? This makes you comfortable delivering a complete origin judgment rather than half of one. Remember that thresholds and rule details come from each specific agreement and from the jurisdiction's own non-preferential rules; the two-step structure is the learnable part, while the numbers must be checked against the agreement text you are studying.
Procedures and documents: how a declaration carries your classification and value decisions
The procedures topic concerns how classification and valuation decisions are made and sustained: declaration data, supporting documents, and how authorities can query, amend, or review a decision afterward. Practice the rules as a shipment lifecycle.
The shipment lifecycle pins the paperwork in sequence: the commercial invoice and packing list from the exporting side, transport documents, origin evidence, and the import declaration, which carries the classification code, the dutiable value, and any rate claim. Drill by mapping each document to the specific declaration element it supports: which fields support the value, which support a preferential claim, which support the code. A gap between a document and the element it backs is a sign the decision is not well-founded.
The lifecycle continues after declaration: authorities can raise queries, declarations can be amended, and decisions can be reviewed after clearance. Add a follow-up step to practice scenarios: if a review turns up an undisclosed payment, which valuation question follows, and which documents would establish the basis one way or the other? Treating procedures as the evidentiary backbone of the chain, rather than a standalone memorization list, is what links the separate topic areas into one consistent skill.
Worked scenarios: combining classification, valuation, and origin in one computation
Chain skill grows in scenarios where decisions collide. Beyond solving each step, ask: at exactly what point did I leave GRI 1 or Method 1, and what was my stated basis? Two fully worked examples follow.
Scenario A — a multifunction appliance. An importer declared a coffee maker with a built-in bean grinder under the heading covering grinders. The mistake: choosing the component that came to mind first without running the GRI 3(b) analysis. The better decision: apply GRI 1 and check whether either candidate heading text covers the whole machine; only if both appear to do so move to GRI 3(a) specificity, then to GRI 3(b) essential character. The machine's principal function is brewing, not grinding, so classification follows the brewing function. Why it matters: the resulting code fixes the duty rate used in the third line of the tax chain.
Scenario B — valuation adjustments. A shipment priced at $50,000 excluded (a) a die the importer supplied free of charge for production, worth $1,500, and (b) a $2,000 royalty paid to a licensor as a condition of the sale of the imported goods. The mistake: leaving both out of the base. The better decision: Method 1 adjusts the price upward — the die is an indirect payment for goods produced and not already in the price, and the royalty is paid as a condition of that sale. Dutiable value: $50,000 + $1,500 + $2,000 = $53,500. Because this figure is the base for the third line, the duty and every downstream tax were computed on a $3,500 understatement. Cite the condition each addition depends on; 'assists and royalties are always added' is not a justification.
Self-check exercise and a realistic preparation sequence
The connections between topics are built through integrated problem sets, not topic-by-topic reading. Use this exercise, its rubric, and the sequence below to structure progress, then close with the readiness checks.
Exercise — decision-chain notes. Take ten everyday multifunction products (a phone with a camera, an oven with a toaster function, a fan with a wireless speaker). For each, write two lines: line one, your GRI 1 analysis citing the heading text you relied on; line two, whether GRI 3 is needed and why or why not. Rubric: 2 points per product — 1 point if GRI 1 is applied first with heading text cited, 1 point if the GRI 3 decision is justified, including explaining why 3 is not needed. Maximum score 20; below 16 means your justification steps are the weak link. Do not score rate accuracy yet — the target is order and justification habits.
Preparation sequence (eight weeks at four to six hours weekly; adapt to your schedule): weeks 1–2, GRI-order drills with written justifications before checking answers; week 3, the six valuation methods — reproduce the table from memory, then sketch a scenario where each method is the right one; week 4, adjustments such as assists, commissions, packing, and royalties, each with its include-or-exclude reason; week 5, tax-chain tracing plus reverse reconstruction; week 6, origin in the two-step format; week 7, document-to-declaration mapping; week 8, one integrated problem set per session from classification through the tax chain, writing Scenario A and B style justifications every time. Readiness checks: apply GRI 1 first without reaching for GRI 3; name all six methods in order and explain what blocks each; trace how a duty error moves the downstream tax base; state which rate applies when a preferential claim fails; redo both worked scenarios from memory with justifications. These are learning milestones, not predictions of your result.
- Write a two-line justification for every classification decision before checking the answer.
- Recompute one completed problem with a single changed adjustment and name every downstream line that moves.
- State preferential-origin claims in two steps: rule met and proof exists, then the fallback rate if either fails.
- Map each document in a shipment file to the declaration element it supports.
- Redo the two worked scenarios from memory with written justifications, not just final numbers.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.