José Carlos de Sequeira Costa (18 July 1929 in Luanda, Angola – 21 February 2019 in Olathe, Kansas) was a Portuguese pianist who is especially renowned for his interpretations of the Romantic repertoi
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 0xcd6d94a18a870ef28a9c142a74dffe24a594f7c0472689b9308ff7b1dd397712. Chain 2 (Bitcoin): anchored in block 954055 (2026-06-17T05:51:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/435c08f9-6262-4c92-b59a-2237526b4129.json and https://artists.proofprofile.net/proofs/artist/435c08f9-6262-4c92-b59a-2237526b4129.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
R. Schumann: Piano Concerto In A Minor/Introduction And Allegro Appassionato
Rachmaninov: Piano Transcriptions (Complete)
Schumann, R.: Piano Concerto In A Minor / Introduction And Allegro Appassionato
A Musical Snuff-Box (Sequeira Costa plays Encores)
Etudes, Op. 10 "Chanson de l'adieu": No. 3 in E Major
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 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. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5b0fcdc1dd0cb1aa65b7ae2514879c52241dc5b6d6ede1b07711aec6f565cf42. Chain 2 (Bitcoin): anchored in block 957819 (2026-07-13T07:53:33Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ATMA40509502.
Beethoven: Piano Sonatas Op. 2 Nos. 1, 2, 3
Beethoven: Piano Sonatas Nos. 12, 13, 14, 26
Beethoven: Piano Sonatas Nos. 11, 15, 19, 20
Beethoven: Piano Sonatas Nos. 16, 17, 18
Chopin: The Four Ballades & Sonata No. 3
Manuel Infante, Enrique Granados, Federico Mompou: A Spanish Collection of Classical Piano