Reversi (marketed by Pressman under the trade name Othello) is a strategy board game for two players, played on an 8x8 board (similar to chess and checkers, with the theoretically meaningless difference that the board in reversi is usually monochrome aside from lines separating the individual squares). There are 64 identical pieces called 'disks' (often spelled 'discs'), which are light on one side and dark on the other—physically with an actual set, or conceptually via computer—to correspond with the opponents in a game. In most cases a game consists of placing all of these up to a full board, but exceptions occur if neither player has a legal move. Though the original rules of reversi were such that each player was limited to using no more than half of the disks (those in possession at the start), this rule has long been out of common practice; and, if using a physical board and pieces, the player whose turn it is simply retrieves a disk that is in possession of the opponent as needed. This means that there is now only one way a player will pass (always involuntarily) rather than place a disk, while formerly there were two. Each player's objective is generally to have as many disks one's own color at the end as possible and for one's opponent to have as few—or, technically in consideration of the occasional game in which not all disks are placed, that the difference between the two should be as large as possible if the winner and as small as possible if the loser. However, simply winning is the basic goal, and maximizing the 'disk differential' is regarded as ancillary. (It may have more or less weight depending upon such things as tournament tiebreaks.)

Othello und Reversi sind zwei eng verwandte strategische Brettspiele für zwei Personen.

Othello est un jeu de société combinatoire abstrait, qui oppose deux joueurs : Noir et Blanc.

Othello är ett brädspel som spelas av två spelare på ett 8x8 rutor stort bräde. Spelbrickorna är oftast runda och ljusa på ena sidan och mörka på andra.

Reversi (również Othello) – gra planszowa dla dwóch osób, rozgrywana na planszy o wymiarach 8 na 8 pól przy pomocy 64 dwukolorowych pionów.