How to play Reversi

The board and the discs

The game is played on a board of 8×8 squares. Every disc is black on one side and white on the other: one player plays Black and the other White. When a disc flips, it only changes color – it stays on its square until the end of the game.

Starting position

Every game starts with 4 discs in the center: White on d4 and e5, Black on e4 and d5. Black always moves first.

How to make a move

On your turn, place one disc of your color on an empty square. The move is legal only if it traps at least one of your opponent's discs:

• The trapped discs lie in a straight line – horizontal, vertical or diagonal – between your new disc and another disc of your color.
• Every square between those two discs holds one of your opponent's discs – there are no empty squares in the line.
• All trapped discs flip to your color.
• One move can trap discs in several directions at once. Every trapped line flips.

If a move would not flip any disc, you can't play it.

Example: a first move

In the starting position, Black can play d3. The white disc on d4 is then trapped between the new disc on d3 and the black disc on d5, so it flips to black. After the move, Black has 4 discs and White has 1.

Only discs trapped by the disc you just placed flip. Discs that were already between two of your discs stay as they are.

Example: flipping in several directions

A few moves later, Black plays c5 and traps white discs in 3 directions at once: c4 above it, d4 on the diagonal and d5–e5 to the right. All 4 discs flip.

Passing

If you have no legal move, you pass and your opponent plays again. You can't pass while you still have a legal move. Passes are rare early in the game and happen more often near the end.

End of the game

The game ends when neither player can move. Usually that is because the board is full, but it can happen earlier – for example when one player has no discs left. The player with more discs wins. If both players have the same number of discs, the game is a draw.

In official tournaments, any empty squares left at the end go to the winner. reversi.site simply counts the discs on the board.

Rules on reversi.site

The games on this site follow the rules above. A few details are specific to reversi.site:

• Every game uses the standard start: 4 discs in the center, and Black moves first.
• Passing is automatic. If you have no legal move, the game tells you and your opponent plays again.
• The game ends when neither player can move. The player with more discs wins; equal counts are a draw.
• Online games have a limit of 30 seconds per move (60 seconds for your first move). If your time runs out, you lose the game.
• If your connection drops during an online game, you can rejoin within 60 seconds (at most 2 minutes in total per game).
• Games against the computer and two-player games on one device have no clock.
• Undo is available only when you play the computer, and games in which you use it don't change your rating.
• Against the computer, you can play either Black or White.
• By default, the squares where you can move are marked with a dot.

Notation

Columns are labeled a–h from left to right and rows 1–8 from top to bottom, as in the diagrams on this page. A square is named by its column and row, so d3 is column d, row 3.

A game is written as the list of its moves, for example f5 d6 c3 d3 c4. Passes are not written down: after a pass, the next move in the list is by the same color again.

You can show coordinates on the game board in the settings, and game links on reversi.site use this notation. For example, this link opens f5 d6 c3 d3 c4 – an opening called the Tiger – on the board.

Useful terms

Legal move

A move that traps and flips at least one of your opponent's discs.

Corner

a1, h1, a8 or h8. A disc in a corner can never be flipped. Why corners matter

X-square

A square diagonally next to a corner: b2, g2, b7 or g7.

C-square

An edge square right next to a corner: b1, a2, g1, h2, a7, b8, g8 or h7.

Stable disc

A disc that can never be flipped again, such as a disc in a corner.

Frontier disc

A disc next to at least one empty square. Frontier discs give your opponent places to move.

Mobility

The number of legal moves a player has. Mobility explained

Parity

Who gets the last move – in the whole game or in one region of empty squares. Parity explained

Next steps

• Learn step by step – an interactive guide to your first moves.
• Try the Daily challenge – find the winning moves in a position that looks lost.
• Read the strategy guides – corners, mobility, parity and openings.