The Tetzlaff Quartet is a German string quartet ensemble formed in 1994. The quartet has released four CD recordings, of which their 2014 recording of Berg's Lyric Suite and the Mendelssohn Quartet Op
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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x336ac94343a596d5dff37a36a6281468dc9de3f768b37ff4b6be85d0f566bad3. Chain 2 (Bitcoin): anchored in block 953654 (2026-06-14T16:26:51Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/484ecf3f-1348-49a8-bb28-3d49d0577cab.json and https://artists.proofprofile.net/proofs/artist/484ecf3f-1348-49a8-bb28-3d49d0577cab.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Beethoven: String Quartets, Opp. 132, 130 & 133
String Quartet No. 15 in A Minor, Op. 132: I. Assai sostenuto - Allegro
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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf110909955a6c354c84bd0828ce1318c83d7d09adb102533e0ee8462d3aeb357. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/FINDE2000012.
String Quartet No. 13 in B-Flat Major, Op. 130 (1825 Version): I. Adagio ma non troppo
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0988d87f62658aca128f159dd7a884e896d1b266dfb2d33d72a61a465dc0db64. Chain 2 (Bitcoin): anchored in block 960150 (2026-07-29T21:51:49Z), 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/FINDE2000017.
String Quartet No. 15 in A Minor, Op. 132: II. Allegro ma non tanto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x48f6862b5fb532a17c962b909c29488de1264bb31df95c6152caa5098b881fc6. Chain 2 (Bitcoin): anchored in block 957046 (2026-07-07T14:04:01Z), 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/FINDE2000013.
String Quartet No. 13 in B-Flat Major, Op. 130 (1825 Version): II. Presto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xeb853368868f474a6154e9a4fed52ddb00169815b7f50f77ea188d9bfe5cca7c. Chain 2 (Bitcoin): anchored in block 960185 (2026-07-30T01:32:48Z), 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/FINDE2000018.
String Quartet No. 15 in A Minor, Op. 132: III. Molto adagio
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6c93a27caa544337ffff8d3d86c74f52d6fbf4eb1ba4f3e0823386f1d010bc7d. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/FINDE2000014.
String Quartet No. 13 in B-Flat Major, Op. 130 (1825 Version): III. Andante con moto ma non troppo
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x56f6151979216ec70ca21a7d6982440f6385b672691148cfe7cd0a4d75e89af1. Chain 2 (Bitcoin): anchored in block 960160 (2026-07-29T22:48:59Z), 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/FINDE2000019.
String Quartet No. 15 in A Minor, Op. 132: IV. Alla marcia, assai vivace
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb4b405c5b5caaab59afc27f332e5fa795d79bf488db2ae6e0a439a77cc2940ac. Chain 2 (Bitcoin): anchored in block 960121 (2026-07-29T15:22:21Z), 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/FINDE2000015.
String Quartet No. 13 in B-Flat Major, Op. 130 (1825 Version): IV. Alla danza tedesca. Allegro assai
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x05700df4bac7dd132a6e09b20c0ac172b55ca12d58a4f11b51ecc6eb68ee8f38. Chain 2 (Bitcoin): anchored in block 960266 (2026-07-30T14:44:50Z), 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/FINDE2000020.
String Quartet No. 15 in A Minor, Op. 132: V. Allegro appassionato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x432e28f503da10d14712d8bf760290164c2844d37967c756ba0d639e6edaa327. Chain 2 (Bitcoin): anchored in block 957073 (2026-07-07T18:39:05Z), 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/FINDE2000016.
String Quartet No. 13 in B-Flat Major, Op. 130 (1825 Version): V. Cavatina. Adagio molto espressivo
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x24c60a9b463f5cb3e471cc336700636b9e24163111efdac6943918b511aa8b3e. Chain 2 (Bitcoin): anchored in block 960117 (2026-07-29T14:28:24Z), 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/FINDE2000021.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x610901006a9f6f423acc63dd499bdb0e69721272b30bb9df2fc31b2986d4a5ff. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/FINDE2000022.
Schubert: String Quartet No. 15 - Haydn: String Quartet No. 26
Mendelssohn: String Quartet in a Minor, Op. 13 / Berg: Lyric Suite
String Quartet No. 2 in A Minor, Op. 13, MWV R22: I. Adagio - Allegro vivace
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf8c522ec023c141a0d3c25dfa126feaf7dd33bf984dd6c4f2dbea1695eeb4269. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/DEAQ71426601.
String Quartet No. 2 in A Minor, Op. 13, MWV R22: III. Intermezzo - Allegretto con moto - Allegro di molto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x356989865db4b8675a80221e7db3fa68b1daff77b466333617735bf7eb7efda2. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/DEAQ71426603.
String Quartet No. 2 in A Minor, Op. 13, MWV R22: IV. Presto - Adagio non lento
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdb88979483ed22251592d8ca201e1f07f7019413a2daec76720a83daa09a3ca4. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/DEAQ71426604.