The General Rules for the Interpretation of the Harmonized System (GRIs) are six rules, printed at the start of the HS nomenclature, that decide which heading and subheading a product belongs in. GRI 1 settles most cases: classification is determined by the terms of the headings and the relevant Section and Chapter Notes. GRIs 2, 3 and 4 are used, in that order, only when GRI 1 cannot decide. GRI 5 adds rules for cases and packing, and GRI 6 applies the same method at the six-digit subheading level.
This guide goes through each rule in the HS 2022 wording, gives an example, and points to case studies on this site where the rule decided a real dispute.
Where the GRIs sit in the law
The GRIs are part of the HS nomenclature, which is the annex to the International Convention on the Harmonized Commodity Description and Coding System. Under Article 3 of the HS Convention, each contracting party must use all the HS headings and subheadings without addition or modification, apply the General Rules for interpretation and all Section, Chapter and Subheading Notes, and not change their scope. National tariffs may add their own subdivisions, but only below the six-digit level.
So the GRIs, the heading texts and the legal notes are law in every country that applies the Convention. The WCO Explanatory Notes are different: they are the official interpretation at international level but are not part of the Convention. The distinction is set out in the legal anatomy of HS classification, and the weight tribunals give the Explanatory Notes is covered in the role of the Explanatory Notes in classification disputes.
The GRIs do for classification roughly what accounting standards do for financial reporting: they give everyone the same method, so two people looking at the same product should reach the same heading by the same route. They are applied in sequence. You move to the next rule only when the one before it cannot decide. GRI 5 is the exception in form, because it applies “in addition to the foregoing provisions” to the cases and packing it describes.
GRI 1: the headings and legal notes decide first
GRI 1 reads: “The titles of Sections, Chapters and sub-Chapters are provided for ease of reference only; for legal purposes, classification shall be determined according to the terms of the headings and any relative Section or Chapter Notes and, provided such headings or Notes do not otherwise require, according to the following provisions.”
Two points in that sentence do most of the work. The titles of Sections and Chapters carry no legal weight. And the later rules come into play only if the headings and notes “do not otherwise require”. Most goods are classified at this first step, by matching the product to the heading text and checking the notes.
Example: a laptop computer falls in heading 84.71, “Automatic data-processing machines and units thereof”. Note 6(A) to Chapter 84 defines what counts as an automatic data-processing machine, and a laptop meets that definition, so no further rule is needed to reach the heading.
Always read the Section and Chapter Notes. They are legally binding, and a product that a note excludes cannot go into that Chapter however close the heading text looks. Two case studies on this site turn on exactly this point: a fruit snack that fails a Chapter Note’s three-part cumulative test, and a laptop replacement screen decided by the precedence clause in Note 7 to Chapter 85.
GRI 2: incomplete goods, unassembled goods and mixtures
GRI 2(a) extends a heading that names an article to the article incomplete or unfinished, provided that, as presented, it has the essential character of the complete or finished article. It also covers the complete or finished article presented unassembled or disassembled.
GRI 2(b) extends a reference to a material or substance to mixtures or combinations of that material with other materials, and a reference to goods of a given material to goods consisting wholly or partly of it. Goods made of more than one material or substance are then classified under GRI 3.
Example: a flat-pack table shipped unassembled, with all its parts, is classified as a table, not as a collection of wooden components.
The rule comes up all the time in Asian supply chains, where goods are often imported in semi-knocked-down (SKD) or completely-knocked-down (CKD) form for local assembly. Getting GRI 2(a) wrong changes the duty and can lead to a demand for the difference. The case study on GRI 2(a) and the “as presented” doctrine walks through a 2026 tribunal decision on electric scooter components imported unassembled.
GRI 3: when two or more headings apply
GRI 3 applies when goods are, prima facie, classifiable under two or more headings, whether because of GRI 2(b) or for any other reason. It has three steps, used in order:
- GRI 3(a): the heading that gives the most specific description is preferred to headings with a more general description. When two or more headings each refer to part only of the materials in mixed or composite goods, or to part only of the items in a retail set, those headings are treated as equally specific, even if one describes the goods more precisely.
- GRI 3(b): mixtures, composite goods made of different materials or components, and goods put up in sets for retail sale, which cannot be classified under 3(a), are classified by the material or component that gives them their essential character, insofar as this can be determined.
- GRI 3(c): when neither 3(a) nor 3(b) decides, the goods go in the heading that occurs last in numerical order among those that equally merit consideration.
Example: a gift set of a razor, a shaving brush and soap, put up for retail sale. Each item has its own heading, and each of those headings covers only part of the set, so GRI 3(a) cannot choose between them. Under GRI 3(b) the set is classified in the heading of the item that gives it its essential character, here taken to be the razor. Which item that is depends on the facts of the set (the nature of each item, its bulk, value and role in use), so the answer can change with the product.
GRI 3 comes up constantly with promotional kits, medical test kits and tool sets. For a worked example of all three steps, see the smartwatch comparison, where the Canadian authority found no essential character under 3(b) and reached heading 91.02 through 3(c).
GRI 4: the heading for the most akin goods
GRI 4 reads: “Goods which cannot be classified in accordance with the above Rules shall be classified under the heading appropriate to the goods to which they are most akin.”
It is rarely used, because almost every group of headings ends in a residual “other” heading that catches goods the specific headings miss. When it does apply, it is usually to a genuinely new kind of product that no heading describes at all.
Correction: an earlier version of this guide used a smartwatch with heart-rate monitoring as a GRI 4 example, classified by analogy to heading 85.17 instead of 91.02 on the basis of its principal function. That was the wrong rule. Smartwatches are classified under GRI 1 and GRI 3, and the outcome depends on the product. The European Union’s Implementing Regulation (EU) 2024/964, for example, placed one smartwatch in CN code 9102 12 00 under rules 1, 3(b), 3(c) and 6, and said that watch was not comparable to the article in WCO Classification Opinion 8517.62/23. Other smartwatches have gone to subheading 8517.62. The smartwatch case study linked above sets the two lines of reasoning side by side.
GRI 5: cases, containers and packing
GRI 5(a) covers camera cases, musical instrument cases, gun cases, drawing instrument cases, necklace cases and similar containers that are specially shaped or fitted for a specific article or set, suitable for long-term use and presented with the articles they are meant for. If they are of a kind normally sold with those articles, they are classified with them. The rule does not apply when the container gives the whole its essential character.
GRI 5(b), subject to 5(a), classifies packing materials and packing containers presented with the goods in them together with those goods, if they are of a kind normally used for packing such goods. It is not binding when the packing is clearly suitable for repetitive use.
Example: a violin presented with its fitted case is classified with the violin in heading 92.02, under GRI 5(a). (An earlier version of this guide called this a “set”. A fitted case presented with its instrument falls under GRI 5(a), which is a different rule from the retail sets of GRI 3(b).) A camera bag sold on its own is classified separately, in heading 42.02, which names camera cases.
The question usually comes up with reusable or specialised packaging. Five US rulings on boxes, RFID tags, gas tanks and refrigerant cylinders are analysed in the analysis of GRI 5(b).
GRI 6: classification at subheading level
GRI 6 reads: “For legal purposes, the classification of goods in the subheadings of a heading shall be determined according to the terms of those subheadings and any related Subheading Notes and, mutatis mutandis, to the above Rules, on the understanding that only subheadings at the same level are comparable. For the purposes of this Rule the relative Section and Chapter Notes also apply, unless the context otherwise requires.”
In practice: first fix the four-digit heading, then compare one-dash subheadings with each other, then two-dash subheadings within the chosen one-dash group. A two-dash subheading is never compared with a one-dash subheading of a different group. The mandarin juice case study shows a dispute decided on the exact wording of the lower-level lines, not on how alike two fruits are.
GRI 6 takes you to the six-digit HS subheading. The duty rate attaches to the national tariff line below it, and this is where country-specific tariff variations appear: India’s 8-digit tariff items (also used in the ITC(HS) schedules), the 8-digit ASEAN Harmonised Tariff Nomenclature (AHTN), or China’s 10-digit codes. National tariffs extend the same method to those lines through their own rules and notes.
The GRIs in Asia-Pacific tariffs
In Asia the HS is applied through national tariff schedules such as India’s Customs Tariff and ITC(HS), Singapore’s AHTN-based tariff and Japan’s Customs Tariff. The first six digits are harmonised. How the GRIs play out on a given product can still differ, because national additional notes, national subdivisions and each country’s rulings and case law differ.
A classifier working across these markets has to apply the same GRI reasoning everywhere while checking the national layer each time.
Common mistakes
- Ignoring Section or Chapter Notes, or relying on a Chapter title.
- Jumping to GRI 3 or an “essential character” argument when GRI 1 already decides.
- Misapplying GRI 3 to mixed goods, for example using 3(b) before checking whether 3(a) can decide.
- Comparing subheadings at different levels under GRI 6.
- Failing to write down the reasoning.
- Assuming the same national code applies in every country without checking the tariff variations.
Keep a written justification for each classification that cites the GRIs applied, the notes and Explanatory Notes relied on, and the product specifications. It is the first thing you will need in a post-clearance audit or a dispute. Building an audit-proof HS classification file sets out what such a file should contain, and what GRI fluency actually buys you explains why the written reasoning protects an importer.
To check your own understanding, try the GRI self-assessment, a multiple-choice quiz on applying the rules (registration required).
This guide quotes the HS 2022 edition. HS 2028 enters into force on 1 January 2028, and the examples above should be rechecked against it then.