thumb|right|upright=1.5|Flight of King Gradlon, by E. V. Luminais, 1884 (Musée des Beaux-Arts, Quimper) Ys (pronounced ), also spelled Is or Kêr-Is in Breton, and Ville d'Ys ("City of Ys") in French,
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5f66e6d6d1a0549e00b92dbc7881bc79ca29936e98685f43460d6be717c17def. Chain 2 (Bitcoin): anchored in block 954623 (2026-06-20T23:40:06Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/cb0aea11-bde6-4842-9858-083a681b47f5.json and https://artists.proofprofile.net/proofs/artist/cb0aea11-bde6-4842-9858-083a681b47f5.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).