How Can I Find Out My COSSY Number?

Written by nicholas robbins Google
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Players of the Yu-Gi-Oh! Trading Card Game from Konami regularly meet to test their skills against each other in local and national tournaments. Konami oversees these tournaments through its Konami Digital Entertainment (KDE) division. KDE sets all tournament rules, dates and qualifier conditions for the annual Yu-Gi-Oh! season. Players competing in official KDE tournaments must register for KDE membership. Registration provides players with a personalised Konami Card Game Official Tournament Support System (COSSY) ID number. This number identifies the player's rank and standings for all official Yu-Gi-Oh! tournaments.

Skill level:
Moderately Easy


  1. 1

    Locate the number in the upper-right corner of your KDE registration card. Event organisers distribute KDE registration cards to first-time attendants of sanctioned Yu-Gi-Oh! tournaments. Local card shops with regular Yu-Gi-Oh! events may also register players and provide cards outside of regular event schedules.

  2. 2

    Contact the event organiser at any KDE-sanctioned event. Players with damaged or lost KDE registration cards may request this information in person from any event organiser. The event organiser has access to Konami's COSSY player database.

  3. 3

    E-mail KDE support at with your identifying details. Konami requires your name, birthdate and the answer to your COSSY security question. If you have not yet registered a security question, include that information as well.

Tips and warnings

  • Carry your KDE registration card in your deck box or a special sleeve in your card folder. This ensures you have your COSSY ID available at all times
  • Konami receives many e-mails during the tournament season; players e-mailing KDE directly may encounter very long response times as major events approach.

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