Othello8×8 board

Goal of the game

Have the most discs of your colour on the board when nobody can move any more.

What counts is the final count, not the count along the way. It is the point every beginner gets wrong.

The legal move

• An 8 × 8 board. Starting position: four discs in the centre, crosswise, two of each colour. Black moves first.
• A move means placing a disc of your colour so as to outflank at least one opposing disc between the disc you place and another of your own.
• Every disc outflanked that way — along a row, a column or a diagonal — is flipped and changes colour.
• A move that flips nothing is illegal. If you have no legal move you pass, but you cannot pass by choice.
• The game ends when neither player can move, often before the board is full.

The counting trap

• The first reflex is to flip as many discs as possible every move. It almost always loses.
• Every disc you flip is a disc your opponent can flip back. A big lead at move 20 is worth nothing at move 60.
• Good players are often behind on the count until three quarters of the way through… and are in fact winning thanks to that deficit.
• What matters during the game is not the number of discs: it is the number of moves available.

Mobility

• Mobility is the number of legal moves you have. The more you have, the more you choose; the fewer your opponent has, the more they are forced.
• Middle-game goal: keep few discs, well placed, and cut down your opponent’s options.
• An opponent with no legal move must pass: you play twice in a row. It is often decisive.
• Keep your discs grouped in the centre: a compact mass gives more moves than a spread-out frontier.

Corners and the squares to avoid

• The four corners can never be flipped. A disc in a corner is yours for the whole game, and it stabilises the whole diagonal and the adjacent edges. Corners win games.
• X-squares — the diagonal squares next to the corners — are the worst on the board: playing there hands the corner to your opponent.
• C-squares — the edge squares next to a corner — are almost as bad, for the same reason.
• A simple rule that makes you improve fast: never touch the X-squares, and only go to C-squares if you know why.

The mistakes that cost the most

• Flipping as many discs as possible every move. Mistake number one, and the most stubborn.
• Taking the edges too early. A poorly supported edge gets flipped and opens a corner.
• Forgetting to count your legal moves. Before playing, look at how many your opponent will have left.
• Celebrating a big lead in the middle game. It is often a sign that you are losing.

Controls

Keyboard and mouse

• Playable squares are marked; click to place a disc.
• Flipped discs are animated, so you can follow the effect of the move.
• The counter shows the current score and how many moves each player has.

Touch screen

• Tap a marked square. Illegal squares do not react.
• A forced pass is shown when you have no move.
• With two players, pass the device after each move.

Frequently asked questions

Are Othello and Reversi the same game?

Almost. Othello is the standardised modern version: a fixed starting position and an 8 × 8 board. Historical Reversi let the first discs be placed freely.

Can you pass your turn on purpose?

No. You only pass when no legal move exists, and then it is mandatory.

Why are corners so important?

Because a disc in a corner can never be outflanked, so it can never be flipped. It also stabilises the discs lined up from it.

Should you flip as many discs as possible?

No, it is the classic trap. A disc flipped today gets flipped back tomorrow. Aim instead to limit your opponent’s possible moves.

Does the game always end with a full board?

No. It ends as soon as neither player can move, which often happens before the 64th square.

More classics, free as well

• Pelotes — the flick, three colours, the mega bonus
• Petits chevaux — four horses, a 6 to get out, the final staircase
• Piaf — flap your wings, clear the pipes, start again