# NCX 2005-1

Source: https://xmlvalid.com/schemas/epub-2-ncx

> The NCX navigation file of EPUB 2 books, also kept in many EPUB 3 books for older readers.

The NCX (from DAISY Z39.86) is the table of contents of an EPUB 2 book. EPUB 3 replaced it with the navigation document but allows it for compatibility.

- Type: RelaxNG
- Version: 2005-1
- Namespace: `http://www.daisy.org/z3986/2005/ncx/`
- Root element: `ncx`
- Publisher: W3C EPUB 3 Community Group (epubcheck) (BSD 3-Clause (epubcheck)), source: https://github.com/w3c/epubcheck/tree/main/src/main/resources/com/adobe/epubcheck/schema/20
- Validate against it: https://xmlvalid.com/validate?schema=epub-2-ncx

## Notes

- Only the grammar is checked: epubcheck's NCX rules use the pre-ISO Schematron namespace, which the rule compiler here does not read. Whether the content links resolve is not checked.
- The example is by xmlvalid.com.