Tariff classification rules define how excise goods are identified through headings, sub-headings, essential character, and packing treatment. General rules govern classification of goods under the First Schedule to the Central Excise Tariff Act, 1985 by giving legal primacy to the terms of headings and relevant Section or Chapter Notes, while treating section, chapter and sub-chapter titles as aids to reference only. The interpretative scheme addresses incomplete or unfinished articles, unassembled or disassembled goods, mixtures, composite goods, goods put up in sets for retail sale, and goods consisting of more than one material or substance, with classification determined by specific description, essential character, or numerical order where necessary. The rules also provide for classification of goods not otherwise classifiable by reference to likeness or affinity, and lay down special treatment for containers and packing materials presented with goods. In addition, sub-heading classification is to be determined by the terms of the sub-headings and related notes, applying the same interpretative principles mutatis mutandis, with comparison limited to sub-headings at the same level. General explanatory notes clarify the use of indentation in tariff descriptions and the meaning of percentage-based duty entries by reference to valuation provisions under the Central Excise Act, 1944.