Guide
How to Play Reversi (Othello)
Reversi is a game of position and timing. Sandwich the opponent's discs to flip them, fight for the corners, and finish with more discs on the board than your opponent.
Play ReversiThe objective
Finish with more discs than your opponent
Reversi is played on an 8x8 board between two colours, Black and White. You win by having more discs of your colour on the board than your opponent when the match ends — usually because the board has filled up, though a match can end earlier if neither side has a legal move.
Between the opening and the final count, the work is choosing where to place each disc so it traps a line of your opponent's discs and flips them to your colour — while thinking ahead to what you hand your opponent in return. There is no timer forcing your hand; the challenge is reading a few moves ahead.
The game is free, runs in the browser, and needs no account. Open the board when you want to play; use this guide for the rules, the difficulty levels, and the habits that beat the computer more often.
The setup
Four discs at the centre, Black to move
Every match starts the same way: two Black discs and two White discs sit at the centre of the empty 8x8 board, arranged diagonally so each colour faces the other across the middle. Black always plays first, regardless of whether you or the computer is playing Black.
Choose your colour and a computer difficulty on the deal screen before you start. If you choose White, the computer opens the match with Black's first move automatically.
Controls
Tap, click, or use the keyboard
Every legal square is marked for you — pick whichever input fits the device in your hand.
Everywhere
Tap or click a square
Every empty square that is currently a legal move is marked with a soft dot. Tap or click one to place your disc — every line it captures flips with a short cascading animation.
Stuck for an idea
Hint
The hint button highlights one strong legal move, chosen by the same search the computer uses to think, so you can see a good idea without giving up the turn.
Desktop
Keyboard
U undoes your last move (and the computer's reply with it), H asks for a hint, N starts a new match, and M mutes the sound. Every on-screen control also has a visible focus ring for keyboard navigation.
The loop
Four ideas that repeat all match
Reading the board, then choosing between these four is the whole game.
- 1
Read the opening position
Reversi starts on an empty 8x8 board with four discs already placed at the centre: two Black and two White, arranged diagonally so each colour faces the other. Black always moves first.
- 2
Sandwich to flip
Place a disc of your colour on an empty square so that it traps one or more of the opponent's discs in an unbroken straight line — horizontal, vertical, or diagonal — between your new disc and another disc you already own. Every trapped disc flips to your colour immediately.
- 3
Capture is mandatory
You may only play a square that flips at least one opponent disc. If you have no legal move anywhere on the board, your turn is skipped automatically and play passes back to your opponent.
- 4
Win by majority
The game ends the moment neither player has a legal move — usually when the board is full. Whoever owns more discs at that point wins. A tie is possible if both colours end level.
Rules
Every rule that decides a move
The objective
Finish the match with more discs of your colour on the board than your opponent. The match ends the instant neither player has a legal move.
Legal moves
A move is legal only on an empty square that sandwiches at least one opposing disc — in a straight, unbroken line of the opponent's colour — between the new disc and an existing disc of your own colour. A move that flips nothing is not allowed.
Flipping
Every opposing disc caught in a valid sandwiched line flips to the mover's colour, in every direction the move captures at once. Flipped discs can be flipped back again later in the game by either side.
Passing
If a player has no legal move anywhere on the board, their turn is skipped automatically and play returns to the other side. Passing is not optional and is not a choice the player makes.
Game end and winner
The match ends when neither Black nor White has a legal move — typically because the board is full, though it can happen earlier. Whoever has more discs on the board at that moment wins; equal counts are a tie.
Difficulty levels
Easy, Normal, or Hard
Pick the computer's difficulty on the deal screen; stats are kept separately for each.
- 01 · A relaxed opponent
Easy
The computer mixes in a good share of random legal moves and only looks one move ahead the rest of the time. It rarely fights hard for the corners, which makes Easy the right place to learn the flipping rules without punishment.
- 02 · A fair fight
Normal
The computer searches a few moves ahead and weighs the board using corner and edge control, so it plays solid, sensible Reversi. Careless corner giveaways get punished, but a well-played game is winnable.
- 03 · Plays to win
Hard
The computer searches deeper, prioritises mobility and corner control from the opening, and solves the endgame exactly once few squares remain. Beating Hard takes real planning, not just avoiding obvious mistakes.
Common mistakes
Why winnable games get lost
Chasing disc count too early
Flipping the most discs on a given turn feels productive, but it often opens a corner or edge for your opponent next turn. Weigh what you give away, not just what you gain.
Playing next to an open corner
The X-squares and C-squares that border an empty corner are traps: playing them can hand your opponent the corner itself, which they can never lose again.
Ignoring mobility
A player boxed into very few legal moves is often forced into a bad one, or into passing at the worst moment. Keep options open rather than filling the board as fast as possible.
Losing track of the endgame count
As the board fills up, the right move stops being about position and becomes pure arithmetic. Recount the discs before every move in the last ten squares or so.
- Corners can never be flipped once taken — fight for them and avoid handing them away.
- Never play the square diagonally next to an empty corner (the "X-square") unless it forces your opponent into a worse reply.
- Early in the game, disc count barely matters — mobility (how many legal moves you have) matters far more.
- A move that limits your opponent's options is often better than one that flips the most discs right now.
- Edge squares next to a corner ("C-squares") are risky before the corner itself is settled — they can hand the corner away.
- In the endgame, once the board is nearly full, disc count is everything — count carefully before your final moves.
- Use undo to compare two candidate moves before you commit; there is no penalty for checking your idea first.
Where you can play
Same game on phone and desktop
reversigame.app runs in any modern browser with no app to install. Progress stays on the device you played on.
Desktop browsers
Chrome, Edge, Firefox, and Safari all run the game with no plugin. Click a highlighted square to play, use the keyboard shortcuts for undo, hint, and a new match, or mute with a click.
Phones and tablets
The board is touch-first and scales to fit the screen. Tap a highlighted square to place a disc, and dealing a new match is instant with no page reload.
Progress on this device
Wins, losses, ties, best margin, fastest win, and win streak are tracked separately for Easy, Normal, and Hard in local browser storage. They stay until you reset them or clear site data, and they do not sync between devices.
Still stuck on a rule? Read the Reversi FAQ or jump in and play.
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