# What is the books hash?

A hash chained over each committed window of book entries, rule R13; the Sync page shows the latest.

URL: https://blockspace.wiki/answers/what-is-the-books-hash/

The books hash, or [consensus hash](https://blockspace.wiki/glossary/consensus-hash/), is rule R13 of BTI's ruleset: each committed window of book entries is chained into one hash. block.space's Sync page shows the latest window. On 2026-10-21 it covered blocks 972,300 to 972,399, with 361,951 entries, and showed the hash's first sixteen hex digits, b734098827f672a2.

Sources:

- Blockspace Co. records
- block.space Sync page: the three tiers, their heights and the latest consensus-hash window · https://block.space/sync

Updated: 2026-10-21