Player Responsibilities A . Player ID / COSSY ID Number . COSSY is the global player identification and ranking system used by KDE . You must register for a Konami Player ID card with a COSSY barcode and number in order to participate in a Sanctioned event . Once your ID card has been issued , it is your responsibility to not lose the ID card and / or your COSSY barcode sticker . You will be required to present this information when registering for a tournament . Your ID card and barcode stickers are yours and may not be used by anyone else for any purpose . After receiving your card , COSSY barcode , and number , you need to register your number online at https : / / www . cossy . konami . net . Until you register your number with your personal information , your ranking cannot be tracked . You are responsible for the maintenance of your own COSSY information . This includes keeping contact information up to date , as well as regularly reviewing your tournament history for accuracy . You may register for only one Konami Player ID at a time . You should consider memorizing your 10 - digit COSSY ID number , as well as keeping a photocopy , digital picture , or scan of your barcode ; so that you can print out a new one in the future if necessary . If you have questions about your COSSY ID that are not covered above , please contact < br > us - opsupport @ konami . com ( North America ) , la - opsupport @ konami . com ( Latin America and the Caribbean ) or yugioh @ konami - europe . net ( Europe , South Africa , Australia , and New Zealand ) . B . Identification . You should be prepared to produce personal identification if asked to do so by a tournament official . School ID cards , state ID cards , driver ’ s licenses , passports and birth certificates are all valid forms of identification . You may contact the Tournament Organizer ahead of time if you have questions about providing identification . Approved identification is required at all events with an age limit or an invite structure . This includes , but is not limited to Regional Qualifiers , Dragon Duels , Yu - Gi - Oh ! Championship Series , and World Championship Qualifiers . C . Tournament Materials . You must bring a tournament legal Deck ( to constructed events ) ; as well as extra card sleeves , paper and pencils to track scores and fill out Match Result slips , and any dice , coins , counters or tokens that your Deck requires . You may use a calculator to help keep track of score , but must keep a paper record as well to help resolve disputes . In addition to tournament supplies , you must bring the appropriate entry fee , your Konami Player ID card and / or COSSY barcode sticker , and personal identification . D . Understand Rulings . You should read and understand the latest version of the rulebook for the game you are playing , as well as look over rulings that apply to the cards you have included in your Deck . While there will be judges at a Sanctioned tournament , you will have a better tournament experience if you prepare yourself beforehand by knowing what your cards do , and how the game works . E . Unacceptable Behavior . Participants in all Sanctioned Konami tournaments are expected to display good sportsmanship when interacting with other tournament attendees , players , judges , and staff . Rude language , disruptive or disrespectful behavior , inappropriate clothing or supplies , unwarranted accusations , and disregard for the safety of others or the condition of the venue will not be tolerated . You should read the Penalty Guideline document before attending an event , to better understand how you are expected to behave . If an attendee arrives at an event intoxicated or under the influence of any substance , or becomes so during the course of the event ; he or she will be Disqualified and removed from the venue and may be subject to additional penalties . F . Communication . It is your responsibility to relay accurate information at all times . You should clearly communicate your actions during game play , and ask questions of your opponent or a tournament official if you are unsure about something . You are obligated to notify an opponent if he or she fails to follow any game rules , including effects he or she may be playing incorrectly . Failure to do so may result in penalties . Players should request the assistance of a judge at the time an issue arises , rather than afterwards . Players may not retract moves once they have committed to them . " Click here to return to TRADING CARD GAME Tournament Policy . "