The Harmonized Commodity Description and Coding System (known as the Harmonized System), instituted by the World Customs Organization in 1988, is an international product classification for customs tariffs and trade statistics.  It is applied by more than 190 countries or customs territories, which are either signatories to the HS Convention or applying the HS on a de facto basis.  The HS product classification is broken down by Sections, Chapters, Headings and, at its most detailed level, Subheadings (HS 6-digit codes).  The HS product classification is logically structured and supported by rules and definitions to achieve uniform classification.  The HS was developed as an extension of the former 4-digit CCCN heading to the 6-digit HS heading and was amended in 1992, 1996 and 2002, as follows:

Nomenclature:	CCCN	HS 1988	HS 1996	HS 2002
Sections:	21	21	21	21
Chapters (2-digit items)	99	96	96	96
Headings (4-digit items)	1011	1241	1241	1244
Headings (5-digit items)	-	3558	3576	3599
Sub-headings (6-digit items)	-	5019	5113	5224

In customs tariffs, the first six digits of the tariff line number correspond to the relevant HS 6-digit subheadings.  Many countries have expanded their national tariff nomenclature beyond the HS 6-digit level to 8-digit and even 10-digit tariff lines, to suit their domestic requirements for product classification and duty collection.  Beyond the HS 6-digit level, customs tariffs sometimes also contain tariff heading descriptions covering several tariff lines in order to avoid the repetition of very long product descriptions.  No duties are attached to tariff heading descriptions.

See FORMULA APPROACH.

See HARMONIZED SYSTEM (HS).

INRs on concessions negotiated at a level higher than that currently in force for a given tariff item. Historical INRs are shown in column 7 of the WTO loose-leaf schedules. See also INITIAL NEGOTIATING RIGHT(INR) and FLOATING INITIAL NEGOTIATING RIGHTS.