A4
type: MusicGroup
description: A4 commonly refers to: A4 paper, a paper size defined by the ISO 216 standard, measuring A4 and variants may also refer to: Science and technology British NVC community A4 (Hydrocharis morsus-ra
popularity: 12
followers: 2634
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0x87e8dad87a1c0700e3839458ff7085a6bc2e2da9294af667d732959eb83f7730
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
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additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/953770
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/ac692666-2956-44ed-a375-82911c2492ec.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/ac692666-2956-44ed-a375-82911c2492ec.json
additional property: OTSVerificationAPI
  type: PropertyValue
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additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-15T09:50:11Z
additional property: OTSCanonicalRecord
additional property: OTSVerifyInstructions
  type: PropertyValue
  value: 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
subject of: OpenTimestamps Proof of Existence
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  encoding format: application/vnd.opentimestamps.ots
  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x87e8dad87a1c0700e3839458ff7085a6bc2e2da9294af667d732959eb83f7730. Chain 2 (Bitcoin): anchored in block 953770 (2026-06-15T09:50:11Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/ac692666-2956-44ed-a375-82911c2492ec.json and https://artists.proofprofile.net/proofs/artist/ac692666-2956-44ed-a375-82911c2492ec.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-15T09:50:11Z
album: Quando Me Pedes P'ra Dançar
  type: MusicAlbum
  date published: 1999-05-10
album: A4: Changes
  type: MusicAlbum
  date published: 2013-07-01
album: HARAKIRI (feat. Yousless)
  type: MusicAlbum
  date published: 2019-01-30
album: Robot Rock
  type: MusicAlbum
  date published: 2019-06-21
album: Рвать на битах
  type: MusicAlbum
  date published: 2020-06-05
album: Рвать на битах
  type: MusicAlbum
  date published: 2020-06-05
album: Kids Phonk
  type: MusicAlbum
  date published: 2020-10-16
album: 動員日
  type: MusicAlbum
  date published: 2022-02-25
album: 58毫米
  type: MusicAlbum
  date published: 2022-02-25
album: John Wixk
  type: MusicAlbum
  date published: 2022-04-01
album: Ahh Ha Remix
  type: MusicAlbum
  date published: 2022-05-01
album: Pop Out
  type: MusicAlbum
  date published: 2022-05-15
album: GIFT FOR MOM
  type: MusicAlbum
  date published: 2023-01-05
album: Hold Me Close
  type: MusicAlbum
  date published: 2023-02-14
album: Say Bye
  type: MusicAlbum
  date published: 2023-04-12
album: There Is No Night Or Day LP
  type: MusicAlbum
  date published: 2023-08-11
album: Body Snatchers
  type: MusicAlbum
  date published: 2024-04-16
album: Four Rays
  type: MusicAlbum
  date published: 2024-10-04
track: Beautiful warrior My self (feat. yamada.)
  type: MusicRecording
  duration: PT2M50S
  duration ms: 170084
  explicit: false
  by artist: A4
  by artist: yamada.
  in album: CHUNITHM LUMINOUS ORIGINAL SOUND TRACK
    type: MusicAlbum
    date published: 2024-12-12
  isrc code: TCJPC2464255
  additional property: CopyrightID
  additional property: CopyrightStatus
    type: PropertyValue
    value: registered
  additional property: CopyrightRegisteredAt
  additional property: CopyrightChainExplorerURL
    type: PropertyValue
    value: https://explorer.copyrightchains.com/tx/0xb7379ec259f70bc8ffe193d5b6f8d62e77cb13bcf06cebdd70ab59c610e2f60e
  additional property: OTSHash
  additional property: OTSBitcoinBlock
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    value: 960108
  additional property: OTSBitcoinBlockVerifyURL
    type: PropertyValue
    value: https://blockstream.info/api/block-height/960108
  additional property: OTSVerificationAPI
    type: PropertyValue
    value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/TCJPC2464255
  additional property: OTSTimestamp
    type: PropertyValue
    value: 2026-07-29T13:09:35Z
  additional property: OTSVerifyInstructions
    type: PropertyValue
    value: 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
  subject of: OpenTimestamps Proof of Existence
    type: DigitalDocument
    encoding format: application/vnd.opentimestamps.ots
    description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb7379ec259f70bc8ffe193d5b6f8d62e77cb13bcf06cebdd70ab59c610e2f60e. Chain 2 (Bitcoin): anchored in block 960108 (2026-07-29T13:09:35Z), 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/TCJPC2464255.
    date published: 2026-07-29T13:09:35Z
  audio: Beautiful warrior My self (feat. yamada.)
    type: AudioObject
    additional property: Tempo (BPM)
      type: PropertyValue
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    additional property: Musical Key
      type: PropertyValue
      value: 0
    additional property: Mode (Major/Minor)
      type: PropertyValue
      value: 1
    additional property: Time Signature
      type: PropertyValue
      value: 5
    additional property: Danceability
      type: PropertyValue
      value: 0.649
    additional property: Energy
      type: PropertyValue
      value: 0.79
    additional property: Speechiness
      type: PropertyValue
      value: 0.051
    additional property: Acousticness
      type: PropertyValue
      value: 0.03
    additional property: Instrumentalness
      type: PropertyValue
      value: 0
    additional property: Liveness
      type: PropertyValue
      value: 0.283
    additional property: Valence (Positivity)
      type: PropertyValue
      value: 0.842
    additional property: Loudness (dB)
      type: PropertyValue
      value: -12.27
    additional property: Key Name
      type: PropertyValue
      value: C
    additional property: Mode Name
      type: PropertyValue
      value: Major