# ISBN — a valid GTIN-13 in 978/979

> The ISBN registry row: ISBN-13 as a GTIN-13, the ISBN-10 mod-11 rail and 10→13 conversion, and the honest license posture on book enrichment.

- page: https://barcoding.dev/schemes/isbn/
- machine row: https://barcoding.dev/schemes/isbn.json
- scheme (dotted registry name): isbn

## Reference
- grammar: ISBN-13: a GTIN-13 in the 978/979 prefix — registration group, registrant, publication, check digit. ISBN-10: nine data digits plus a mod-11 check where X renders 10.
- check: ISBN-13: GS1 mod-10 (it is a GTIN). ISBN-10: mod-11 with 10 rendered X. Conversion: drop the ISBN-10 check, prefix 978, recompute mod-10.
- canonical: The ISBN-13 / GTIN-13 form; all three printed forms of the same book canonicalize together.
- barcode types: EAN-13 above the Bookland barcode; the same number on the copyright page in hyphenated form
- enrichment: routed to book enrichment — posture stated honestly: sanctioned dumps with license unstated are confirm-before-redistribution; display-only sources stay display-only
- join: 978/979 detection is a declared precedence inside GTIN space: the ISBN reading is stated, the GTIN validity keeps holding.

## Registry rows (engine artifacts, digest-stated)
### isbn
- grammar: `^(97[89]\d{10}|\d{9}[\dX])$`
- check: isbn → "mod11 pass" (ISO 2108; ISBN-13 is a Bookland EAN-13 (mod-10))
- canonical: ISBN-13 (978/979 Bookland EAN)
- segments: prefix · registration group · registrant · publication · check
- generate: ean13
- hand-off: read here · resolved by id.org.ai
- digest: sha256:629908b0992134e8219c00b143f432cbb88e68f5c141a50e37ff238371e1c5b7

## Resolution stance
barcoding.dev detects, parses, verifies, enriches and generates — the codec and the data layer. Resolution — an identifier answered with identity and its linkset of live doors — is ONE capability family-wide, served by the family's identity layer, id.org.ai; vertical estates project the same one capability (vehicles: auto.dev). This registry row is the data that resolution consumes.

## Posts
- https://barcoding.dev/blog/isbn-is-a-gtin/