This was an early attempt to track the value of cards for Duelists in the OCG, as "replica" cards would be worth less compared to Original Print cards that were originally only obtainable by participating in or even winning an official tournament.
In the Japanese and Asian-English OCG, replica is used on reprints of cards that were originally printed as invitation, attendance, participation, or prize cards for the Yu-Gi-Oh! Duel Monsters II: Dark duel Stories Duelist Legend in Tokyo Dome tournament; for reprints of the Yu-Gi-Oh! Duel Monsters III: Tri-Holy God Advent Official Tournament Street Duel Legend of Power prize card; for all prints of Match winners (except "Victory Dragon"); for all reprints of the original Egyptian God Cards; for the Ritual Monster counterparts of the Yu-Gi-Oh! Duel Monsters National Tournament prize cards; and (seemingly mistakenly due to being included in Premium Pack 3) all reprints of "Meteor Dragon" and "Black Magic Ritual".
In addition to their original print, reprints in the Asia Championship 2001, Structure Deck: Yugi, the Anniversary Pack, the Yu-Gi-Oh! The Dark Side of Dimensions Duel Set, and Structure Deck: Yugi Muto are not marked as replicas. All Japanese and Asian-English prints of Match winners (except "Victory Dragon") and the Ritual Monster counterparts of the Yu-Gi-Oh! Duel Monsters National Tournament prize cards use replica, including the original OCG prints. Additionally, replica reprints of the original Yu-Gi-Oh! Duel Monsters National Tournament prize cards were released through some unknown means.
In the Korean OCG, prior to the release of Millennium Deck, replica was exclusively used on Match winners (except "Victory Dragon"). From Millennium Deck onward, replica is printed on Korean cards that are also printed as replicas in the Japanese OCG.
In the Japanese OCG, replica is formatted "Replica" on cards that are not Match winners. In all other language releases as well as Japanese Match winners, replica is formatted "REPLICA".
For Match winners that are not Pendulum Monsters, due to having Limitation Text, instead of being printed in the bottom left corner in lieu of the passcode, it is instead printed on the left side of the card between the artwork and lore box, where Edition text like "Limited Edition" is printed in the TCG prior to Series 9.
For Match winners that are Pendulum Monsters, due to having Limitation Text and no room between the artwork and lore box, REPLICA is placed to the right of the Card Number. If a Match winner Pendulum Monster would have edition text and is a replica, the Edition text is simply omitted (even if the other cards in the same set are not Unlimited Edition).
In the TCG and Korean OCG, if a replica non-Pendulum Monster also has edition text, REPLICA is slashed with the edition text, with REPLICA being listed first.