Reversi (also known as Othello) is a strategy game for two players. It is played on a 8x8 square board. Each player has a color (black or white) and aim of the game is to have more of your colored pieces on the board than your opponent's once no empty square is left in the board.
The game starts with four pieces on the board, two white and two black. You capture opponent's pieces if after placing your piece opponent's pieces are surrounded by your pieces at two ends in a straight line (horizontally, vertically or diagonally). The surrounded opponent pieces are captured and flipped over to your color.