Reversi — sold commercially as Othello and famously described as taking 'a minute to learn, a lifetime to master' — is a brilliant game of sudden reversals. This free online Reversi game runs in your browser against a computer opponent, with no download or sign-up needed.
You place discs to trap your opponent's discs between two of your own, flipping them to your colour. The lead can swing wildly right up to the final move, which makes every game tense to the very end.
Reversi was invented in England in the 1880s, when two rival Victorian designers — Lewis Waterman and John Mollett — each claimed to have created it. It was sold by the London firm Jaques and Son and became a parlour hit of the era.
The game was reborn in 1970s Japan, where Goro Hasegawa refined and marketed it as Othello, naming it after Shakespeare's play, with the black-and-white discs echoing the drama's themes of conflict. Under that name it became a worldwide bestseller, and its clean rules made it another early target for game-playing computers, which now play it far beyond human strength.
The goal is to have more discs of your colour on the board when no more moves are possible. On your turn you place one disc so that it traps a straight line of one or more enemy discs — horizontally, vertically or diagonally — between the disc you just placed and another disc of your colour. Every trapped disc in that line flips to your colour.
You may only play a move that flips at least one disc. If you have no legal move you must pass, and if neither player can move the game ends. The board starts with four discs in the centre, and from there it fills up until it is full or locked.
Legal moves are marked on the board; click any highlighted square to place your disc and flip the trapped line. If you have no legal move, play passes automatically to your opponent.
The great trap of Reversi is thinking that more discs is better. In fact, having fewer discs in the middlegame is often an advantage. These principles explain why.
Take the corners. Corner discs can never be flipped, because there is no square beyond them to complete a trap. They are the anchors of the board and the single most valuable squares — grab them whenever you safely can, and build stable rows outward from them.
Beware the squares next to corners. The squares diagonally next to an empty corner (the X-squares) are dangerous: playing one usually hands your opponent the corner. The edge squares beside corners (the C-squares) are risky for the same reason. Avoid both until the neighbouring corner is settled.
Play for mobility, not maximum flips. Counterintuitively, flipping the most discs early is bad — it gives you a big, brittle blob and fewer safe moves later. Aim instead to keep your disc count low and your options high, forcing your opponent into the bad squares.
Limit your opponent's moves. The strongest positions are ones where your opponent has very few legal moves, ideally only bad ones. Think about which squares your move opens up for them, and try to leave them with nothing but corner-giving options.
Build stable edges. Discs along a fully controlled edge, anchored to a corner, cannot be flipped and form a secure base. Solid edges convert into a large stable region once the board fills late in the game.
Count carefully in the endgame. With the last several moves the game becomes concrete: count out the lines and the final disc totals. Parity — who makes the very last move in a region — often decides close games, so plan the ending, not just the next flip.
Practise against the easier AI levels by deliberately keeping your disc count low and refusing the tempting big flips; once the mobility idea clicks, the higher levels become far more beatable.
How do you win at Reversi?
You win by having more discs of your colour on the board than your opponent when neither player can move, usually because the board is full. Controlling the corners and keeping your options open are the keys to finishing ahead.
Why is having fewer discs sometimes better?
Because each move must flip at least one disc, a small, compact position in the middlegame keeps your options open and forces your opponent into weak, corner-giving squares. Piling up discs early often backfires.
What is the difference between Reversi and Othello?
They are essentially the same game. Othello is the trademarked 1970s version with a fixed starting position and standardised rules; Reversi is the older public-domain name. The strategy is identical.
Is this Reversi game free?
Yes — play free in your browser against the computer, with no download and no sign-up.
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