Reversi

Flank your opponent's discs to flip them. The player with the most discs at the end wins.

How to play

Players take turns placing a disc of their colour. Black moves first.

A move must flank at least one line of enemy discs between the new disc and another disc of your colour (horizontally, vertically or diagonally). All flanked discs flip to your colour.
If you cannot make a legal move you pass automatically. When neither player can move, the game ends and the player with more discs wins.
Legal squares are marked on the board when it is your turn.

The game is also played on smaller 6×6 and larger 10×10 boards, each with its own rating.