A character matchup, or a counter, is a prediction on how two characters would fare against each other in tournament settings. For example, the matchup between Meta Knight and Peach favors Meta Knight. This list does not mean that a character has no chance of beating another character in any match, or that players cannot beat a certain character while using any certain character. In addition, this chart does not directly affect tier rankings, nor is it influenced by a character's tier ranking. It simply shows what the general outcome would be if two players with the exact same skill level played each other and used specific characters.
Below is an official chart for Super Smash Bros. Brawl. The chart is incomplete because the information was taken from various character boards on Smash Boards, and not all character boards have completed their matchup discussions. The chart is subject to change. To use it, choose a character from the left side. That character's matchups are displayed in the corresponding row.