Reversi rules and beginner strategy: legal moves, corners and passes

A move must flip at least one opposing disc

Place a disc on an empty square so a straight, unbroken line of opposing discs ends at another disc of your colour. The line may be horizontal, vertical or diagonal. Flip all opposing discs bracketed by that move in every valid direction.

You cannot place a disc merely because it is next to an opponent. Your disc must close the line at the far end, with no empty square in between.

Read one row from left to right

Here B means black, W means white and a dot means an empty square. Black can play at the dot: the two white discs become black because they are bracketed between the new black disc and the existing black disc.

If the row were “. W . B”, the empty space would break the line. That row alone would not make the move legal.

. W W B  →  B B B B

Passing and the end of a match

If you have no legal move, you must pass. If your opponent can still play, the match continues. In our Reversi app this pass is automatic.

The match ends when neither player has a legal move, even if empty squares remain. Count the discs: the player with more wins; equal totals are a draw. In campaign mode, a draw does not clear the level.

Why corners are useful

On a standard rectangular board, a corner disc cannot be bracketed along a line beyond the board, so it cannot be flipped. Before playing next to an empty corner, check whether your opponent could take it on the next turn.

This is a planning aid, not a command to avoid every corner-adjacent move. Count the actual legal replies. Campaign boards can have different shapes, so inspect their edges rather than blindly applying a square-board pattern.

Look at the next move, not just the current count

Flipping the most discs now is not always the strongest choice. Early discs can be flipped back. Compare your candidate moves by the replies they leave your opponent and by whether they give away a corner.

• Choose a legal move and list the opponent’s possible replies.
• Check whether you still have useful moves after that reply.
• Near the end, count the final result rather than relying on an early lead. Use undo to compare lines while practising.

Practise offline against the computer

Our Android Reversi game offers 4×4, 6×6, 8×8 and 10×10 classic boards with three AI difficulty levels. You play black. The campaign contains 500 challenges starting from preset positions.

Play offline without signing in. Optional Google cloud saves sync completed levels and best scores when connected; they do not save an unfinished match. Open the game page for screenshots and the Google Play listing.