Reversi · Complete guide
Reversi: how to play Othello, and how to win
A minute to learn, a lifetime to master. Outflank to flip — and discover that having more discs in the middlegame usually means you are losing.
Reversi — sold as Othello since 1971 — has one rule. Place a disc so that a line of enemy discs is trapped between it and one of your own, and every disc in between flips to your colour. Most discs at the end wins.
From that comes the most counter-intuitive game on this site. Having more discs is usually bad. Every disc you own is a disc your opponent can flip, and a large early group generally means fewer legal moves for you. Strong players deliberately keep their disc count low until about ten moves from the end, then flip everything at once.
What actually matters is mobility — how many moves you have and how few your opponent has — stability, meaning discs that can never be flipped again, and parity, which decides who plays the last move in each region of the board. None of these is visible in the score.
Corners are the exception that everyone can see: a corner disc can never be flipped, which is why the squares beside a corner are the most dangerous on the board.
How to play
The rules take a minute: place a disc, outflank a line, flip everything in between. This guide covers the setup, legal moves, passing, counting, and why the corners and the squares beside them decide almost every game.
Where it comes from
A Victorian parlour game with two rival inventors, rebuilt in Japan in 1971 as Othello, taken apart by a computer in 1997, and finally proved a draw in 2023.
- Reversi was published in England in 1883 with two men claiming to have invented it.
- Victorian Reversi let players place the first four discs; the modern fixed opening came later.
- Goro Hasegawa relaunched the game in Japan as Othello in 1971, and the world championship began in 1977.
- Logistello beat world champion Takeshi Murakami 6–0 in 1997.
How to win
Why flipping fewer discs wins games: corner safety and the low-disc principle for beginners, mobility, frontier and edge play for intermediates, and stability counting, opening theory and exact endgames for advanced players.
- Mobility, stability and parity decide Othello games — the disc count does not, until the end.
- Corners are permanent; the X-squares and C-squares beside them usually give corners away.
- Flip as few discs as possible in the midgame and keep your frontier small.
- Parity means whoever takes the last square in each empty region gains discs the opponent cannot answer.
Common questions
Is Othello the same as Reversi?
Almost. Othello, trademarked in 1971, fixes the starting position and standardises the rules. Nineteenth-century Reversi let players place the first four discs themselves.
Why is having more discs bad?
Because your discs are your opponent's ammunition, and a large group usually means more frontier discs and fewer legal moves. Check your count around move 40 — being behind is often a good sign.
What are X-squares and C-squares?
The squares diagonally next to a corner (X) and beside it along the edge (C). Playing them usually hands your opponent the corner, which is permanent.
Can you pass in Othello?
Only when you have no legal move — and then you must. Running your opponent out of moves is itself a winning strategy.
Is Othello solved?
Yes. A 2023 computational proof showed that 8×8 Othello is a draw with perfect play. It makes no practical difference to human games.
Guides
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