International Standard Book Number
The group identifier code (GIC) number is 0 or 1 for English-speaking countries; 2 for French-speaking countries; 3 for German-speaking countries; 4 for Japanese; 5 for Russian, et cetera. The original standard book number (SBN) had no group identifier, but affixing a zero (0) as prefix to a 9-digit SBN creates a valid 10-digit ISBN. The group identifier may be up to 5 digits long; e.g. 99936 is a group identifier for the country Bhutan.