This whitepaper introduces and formalizes the Proof-of-Recurrence (PoR), the temporal consensus mechanism of the XChronos Project. PoR is a validation methodology based on vector recurrence and temporal density, designed to certify meaningful patterns emerging from the flow of Chronons, Hexacronons, and symbolic events registered within XChronos systems. While traditional blockchains rely on Proof-of-Work (PoW), Proof-of-Stake (PoS) or Proof-of-History (PoH), PoR inaugurates a new paradigm: Proof-of-Recurrence as a symbolic, cognitive, and temporal validation mechanism. PoR ensures that a pattern is only considered valid when it recurs over time, exhibits vector similarity above threshold, generates symbolic density, manifests structural coherence, reaches sufficient significance to form a Hexacronon, and can be certified through the HXS (Hexacronon Score). As a foundational document, this paper expands upon the author’s previous work “Chronons, Hectachronos, and Hexachronons” published on Zenodo. PoR provides the formal validation layer that stabilizes temporal recurrence, establishing the economic and operational substrate of the XChronos framework.