Is Reversi the same as Othello?

Effectively yes. Othello is a standardised commercial version of the Victorian game Reversi, with a fixed starting position, and the two names are now used interchangeably for the same rules.

How does flipping work?

You place a disc so that a continuous line of your opponent’s discs is trapped between it and another of your own discs. Every trapped disc in every direction — horizontal, vertical and diagonal — flips to your colour.

What if I have no legal move?

You pass and your opponent plays again. Every move must flip at least one disc, so if nothing on the board qualifies, you have no choice. If both players pass in a row, the game ends.

Why are the corners so important?

A corner disc can never be outflanked, because there is no square on the far side of it. Corners are the only permanently safe discs, and they anchor stable lines along the edges, so most games are decided by who takes them.

Is it bad to have more discs in the middle of the game?

Usually, yes. Discs on the board are things your opponent can flip, and a large lead in the middlegame often means you have run out of safe moves. Mobility matters far more than the current count until the very end.

Which squares should I avoid?

The four squares diagonally adjacent to an empty corner. Playing one nearly always lets your opponent claim the corner, which is a far bigger prize than any flips you gained.

Reversi

Reversi takes about sixty seconds to learn and rather longer to stop being terrible at. Its central trick is that the obvious good move — flipping as many discs as possible — is usually the wrong one.

Legal squares are marked. Click one to place a disc and flip everything you have outflanked.

Players	2
Deck	8×8 board, 64 two-sided discs
Play time	8–15 minutes
Difficulty	Learn in a minute, lose for years

How to play Reversi

The board is eight by eight and the discs are black on one side and white on the other. The game starts with four discs already placed in the centre — two of each colour, arranged diagonally. Each player owns a colour, and the winner is whoever has more discs of their colour on the board at the end.

The move

You place a disc on an empty square such that, in at least one direction — horizontal, vertical or diagonal — a continuous line of your opponent's discs is trapped between the disc you just placed and another disc of your own. Every trapped disc in every direction flips to your colour.

Concretely: if there is a black disc, then four white discs in a row, and you place a black disc at the far end, all four whites become black. A single move can flip discs in several directions at once.

The constraint that makes the game

Every move must flip at least one disc. If no such move exists anywhere on the board, you must pass and your opponent plays again. If both players pass consecutively, the game is over — though it usually ends simply because the board is full.

The legal squares are marked for you, which is the fastest way to learn the geometry.

Winning

When the board is full or neither player can move, count the discs. Most discs wins. A tie is possible.

Strategy

Reversi punishes greed more directly than almost any board game, because every disc you flip can be flipped back.

The corners are permanent — everything else is temporary

A disc in a corner can never be outflanked, because there is no square beyond it. Corners are therefore the only truly stable discs on the board, and they anchor stable lines along the edges. Nearly every good Reversi game is a fight over four squares.

Never play the square diagonally next to an empty corner

Those four squares — the ones chess players would call b2, b7, g2 and g7 — are the worst squares on the board, and they have a name among Reversi players: the X-squares. Occupying one almost always lets your opponent take the adjacent corner, and taking a corner is worth more than any number of flips.

Having fewer discs in the middlegame is often good

This is the counter-intuitive heart of the game and the reason beginners lose. Discs on the board are targets; each one is a square your opponent may be able to flip. A player with twelve discs and lots of legal options is usually in better shape than a player with forty discs and nowhere safe to move. Count your options, not your discs.

Limit your opponent’s legal moves

Because every move must flip something, a player can be squeezed until their only legal moves are terrible ones — handing you a corner or opening an edge. Playing to reduce their choices, rather than to maximise your own flips, is what strong play looks like.

Play the edges last, not first

Edge discs feel safe because they can only be attacked along one line, but an incomplete edge is a liability: it gives your opponent a way in to the corner. Build edges only when you already hold the corner they lead to.

Variants

Othello — a standardised commercial version with a fixed starting position and a green board. The rules are effectively identical to modern Reversi and the names are used interchangeably.
Anti-Reversi (Reversed) — the player with fewer discs at the end wins, which inverts every principle above.
Free-placement openings — some older rule sets let players place their first two discs anywhere rather than fixing the central four.
Larger boards — 10×10 versions exist and change the corner arithmetic significantly.

Where Reversi came from

Reversi was patented in England in 1888, with rival claims from Lewis Waterman and John W. Mollett, each accusing the other of copying. It sold well as a Victorian parlour game — Waterman's version was published by Jaques of London — and then faded.

Its revival came in Japan in the early 1970s, when Goro Hasegawa marketed the game as Othello, naming it after the Shakespeare play in reference to the black-and-white conflict. That version became enormously popular, and the World Othello Championship has run since 1977. The game also occupies a notable place in artificial intelligence research: because the rules are simple and the branching factor modest, it became a standard testbed, and in 1997 the program Logistello defeated the reigning world champion Takeshi Murakami six games to nil — a more decisive machine victory than Deep Blue's in chess the same year.

Questions people ask about Reversi

Is Reversi the same as Othello?: Effectively yes. Othello is a standardised commercial version of the Victorian game Reversi, with a fixed starting position, and the two names are now used interchangeably for the same rules.
How does flipping work?: You place a disc so that a continuous line of your opponent’s discs is trapped between it and another of your own discs. Every trapped disc in every direction — horizontal, vertical and diagonal — flips to your colour.
What if I have no legal move?: You pass and your opponent plays again. Every move must flip at least one disc, so if nothing on the board qualifies, you have no choice. If both players pass in a row, the game ends.
Why are the corners so important?: A corner disc can never be outflanked, because there is no square on the far side of it. Corners are the only permanently safe discs, and they anchor stable lines along the edges, so most games are decided by who takes them.
Is it bad to have more discs in the middle of the game?: Usually, yes. Discs on the board are things your opponent can flip, and a large lead in the middlegame often means you have run out of safe moves. Mobility matters far more than the current count until the very end.
Which squares should I avoid?: The four squares diagonally adjacent to an empty corner. Playing one nearly always lets your opponent claim the corner, which is a far bigger prize than any flips you gained.