A Mirror Match refers to a match in a game, in which two players face off against each other using the same character (aka dittos), team, etc.
DescriptionEditMirror matches are often done for fun; in high-level play, it also provides the opportunity for players to discover who has the better handle on a given character, and further understand their own playstyles and that of others.
While mirror matches were not technically possible in the original Street Fighter due to there being only one playable character, the two-player mode would pit Ryu against Ken, who at the time shared the same exact moveset, and played exactly the same way.With Street Fighter II': Champion Edition came the true advent of mirror matches, making it possible for players to challenge each other with the same character. In the event that a mirror match is set up and two players pick the same color character, the second player's color palette changes automatically to prevent confusion. Before Champion Edition officialized it, the Super NES version of Street Fighter II: The World Warrior came with a secret code which allowed for Mirror Matches on Versus Mode.
Later games of the Street Fighter series added more potential variables to mirror matches, such as the ISMs of Street Fighter Alpha 3, the different Super Arts of the Street Fighter III series, and the Ultra Combos of Super Street Fighter IV. Many games also have more color palettes to choose from, and characters may have unique win quotes when they defeat their "doubles" in certain modes (e.g: "I am no longer plagued by doubt. Confidence will lead me forward." -Ryu).