There are 6 General Rules for the Interpretation (GRI) of the HS.

These principles of classification, which can be found in Section 1610 of the CMTA, provide for uniform application and interpretation of the HS among HS-using countries.

Each GRI needs to be considered in sequence.

This means that products are first classified using Rule 1. If Rule 1 cannot provide the correct classification of a product, Rule 2 is used. If product classification cannot be determined using Rule 2, then Rule 3 is considered, and so on until Rule 6.