Reversi rules

Board and pieces

In Reversi, two players face off on a 64-square (8x8) board. They also use 64 identical pieces of two colors: one color on the front and a different color on the back.

The game begins with four of the pieces (two of each color) in the four central squares of the board, so that each pair of identical pieces forms a diagonal between them.

Movements

In Reversi, each player plays with one color. On their turn, they must place one piece of their color onto the board. Placed pieces are not moved.

Additions of pieces to the board must be made following these rules:

• A piece can only be added by flanking one or more opposing pieces.
• Flanking is defined as placing a new piece at one end of a row of the opponent's pieces (one or more pieces) at the opposite end of which is a piece of the same color as the new piece, with no empty squares between them. This row can be vertical, horizontal, or diagonal. In this way, the opponent's pieces are trapped between a piece already on the board and the new piece.
• Each time a player adds a piece, and therefore encloses other pieces belonging to the opponent, they must turn the enclosed pieces over, thus making them their own.
• If a single addition causes this flanking situation in more than one line, all opposing pieces involved in each of the flanking moves will be turned over.
• If it is not possible for a player to enclose any piece, they must pass their turn, which then returns to the opponent.

Endgame

The game of Reversi ends when all the squares on the board are occupied or neither of the 2 players has the possibility of adding a new piece.

In any case, the player with the most pieces on the board wins.

A tie can occur if the number of pieces of each color at the end of the game is the same.