were a Japanese idol group that was active from 1998 to 1999. It was formed by Masahiro Mizuguchi, a producer for Fuji TV who had the idea of creating "an Onyanko Club for the Heisei era (1989-2019)"
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 0x130d2b4008826b0e10d1c3f30610e247abc62e124214339957e91b4e698e58aa. Chain 2 (Bitcoin): anchored in block 954618 (2026-06-20T23:05:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c8b5e9b1-965e-43af-9bac-d2f18e3ad81c.json and https://artists.proofprofile.net/proofs/artist/c8b5e9b1-965e-43af-9bac-d2f18e3ad81c.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).