Reversi, also known as Othello, is a classic for two players that takes a minute to learn and a lifetime to master. Trap your opponent's discs between two of yours to flip them, grab the corners and finish with the most discs on the board.
Goal: When nobody can move any more, have more discs of your colour on the board than your opponent.
Two players, Black and White, play on an 8×8 board. Every disc has a black side and a white side; the side facing up shows who owns it.
Four discs start in the centre of the board, two white and two black, with the same colours placed diagonally. Black always moves first.
On your turn you place one disc of your colour on an empty square. The move is only allowed if it outflanks at least one opposing disc: starting from the new disc, in a straight line (horizontal, vertical or diagonal), there must be one or more opposing discs in a row, with no gaps, followed by another disc of your own colour.
The outflanked discs are flipped to your colour. If the new disc outflanks discs in several directions at once, all of them are flipped.
The squares where you can play are marked on the board. Discs are never moved or removed: they only change colour, and a disc may change colour many times during a game.
Only discs that lie on the lines (horizontal, vertical or diagonal) running from the disc you have just placed to another disc of yours can be flipped.
The row of opposing discs must be unbroken and closed by a disc of yours: if it ends at an empty square or at the edge of the board, nothing is flipped in that direction.
All outflanked discs must be flipped, you cannot choose; and discs that have just been flipped do not flip others in a chain reaction.
If you cannot outflank any disc, you have no legal move and you pass: your turn is skipped automatically and your opponent plays again.
You can never pass by choice: if you have a legal move, you must play it.
The game ends when neither player can move. This usually happens when all 64 squares are filled, but it can happen earlier, for instance when one colour has no discs left.
The discs of each colour are then counted: whoever has more discs wins; if the numbers are equal, the game is a draw.
Reversi was born in England in 1883; Othello, patented in Japan in 1971, is its modern version, played in tournaments and world championships. The rules are the same and only the start differs: in the original Reversi the board is empty and the first four discs are placed freely in the centre, in Othello the starting arrangement is fixed, as described above. This game follows the official Othello rules.
Corners are the strongest squares: a disc in a corner can never be flipped. Avoid the squares next to a corner that is still empty, especially the diagonal one: they often hand the corner to your opponent.
In the opening and middlegame, having plenty of moves available matters more than having plenty of discs: flipping few discs and staying flexible is often the best choice.
Try to leave your opponent without safe moves, and count discs only at the end.