At the heart of every accurate HTS classification lies one essential framework: the General Rules of Interpretation (GRIs).
These rules form the foundation for how Customs agencies around the world interpret and apply tariff codes under the Harmonized System (HS).
Without understanding the GRIs, even experienced importers risk inconsistent or indefensible classifications.

This guide breaks down what the GRIs are, how they work, and how to apply them effectively in your day-to-day classification process.

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What Are the GRIs?

The General Rules of Interpretation are six legal principles that determine how goods are classified within the Harmonized Tariff Schedule.
They provide a standardized, hierarchical method for deciding which heading or subheading best describes a product.

Each GRI builds upon the one before it. You must apply them in sequence, starting with GRI 1 and only moving to the next rule if classification cannot be resolved at the previous step.

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GRI 1: Classification by Heading Terms and Section Notes

The first rule states that classification is determined according to the terms of the headings and any relevant Section or Chapter Notes.

That means:

• Read the wording of each heading carefully.
• Check if any Section or Chapter Notes include or exclude certain products.
• If a heading clearly describes your product, the classification ends here.

Example:
A wooden chair is classified under “wooden furniture” based purely on the heading and notes, without needing to apply later GRIs.

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GRI 2: Incomplete, Unassembled, or Mixed Materials

GRI 2 has two parts:

1. GRI 2(a): Incomplete or Unassembled Goods
   If an item is imported incomplete but has the essential character of the finished article, it is classified as the complete item.
   Example: A bicycle shipped without pedals is still a bicycle.

2. GRI 2(b): Mixtures and Combinations
   Goods made of multiple materials or substances are classified as if they were made entirely of the material that gives them their essential character.

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GRI 3: When Goods Seem to Fit Multiple Headings

GRI 3 applies when two or more headings appear to describe a product equally well.
It provides a three-step hierarchy to resolve conflicts:

1. GRI 3(a): The Most Specific Description Prevails
   Choose the heading that most precisely describes the product.

2. GRI 3(b): Essential Character Rule
   If classification cannot be determined by 3(a), classify according to the material or component that gives the item its essential character.

3. GRI 3(c): Last Resort Rule
   If the product cannot be classified under 3(a) or 3(b), choose the heading that appears last in numerical order.

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GRI 4: Goods Not Elsewhere Specified or Included

If a product cannot be classified under GRIs 1 through 3, GRI 4 directs you to classify it under the heading that covers goods most similar to it.
This rule is rarely used but is essential for new or hybrid products.

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GRI 5: Packaging and Containers

GRI 5 clarifies how to classify packaging:

• GRI 5(a): Specially designed cases (like camera cases or musical instrument boxes) are classified with the product they contain.
• GRI 5(b): Ordinary packaging (like cardboard boxes) is classified separately unless it is clearly reusable.

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GRI 6: Subheading-Level Classification

Once the correct heading is found, GRI 6 governs classification within subheadings.
It requires comparing only subheadings at the same level and applying GRIs 1 through 5 in a similar way.

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Why GRIs Matter

Without following the GRIs, classifications can become inconsistent, arbitrary, and vulnerable to audit challenges.
The GRIs ensure that Customs authorities, importers, and exporters speak the same legal language when determining the correct HTS code.

Proper application helps you:

• Reduce classification disputes
• Build defensible documentation
• Ensure accurate duty payments
• Maintain compliance across jurisdictions

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Key Takeaways

• Always apply the GRIs in order, never skipping steps.
• Understand the essential character concept; it appears multiple times across the rules.
• Keep supporting documentation for each classification decision.
• Use CROSS rulings and Explanatory Notes to see how Customs applies these rules in practice.

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Conclusion

The General Rules of Interpretation are the backbone of accurate HTS classification.
By mastering their sequence and logic, importers can navigate even complex or ambiguous products with confidence and legal consistency.

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